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When studying attitudes toward technology education, the affective attitudinal component has primarily been the focus. This study focuses on how the affective, cognitive and behavioral attitudinal components of technology education can be incorporated using a two-step survey: the traditional PATT-questionnaire (PATT-SQSE) and the recently developed Mitcham Score questionnaire. The aim of this study is to explore the relationship among the cognitive, affective and potential behavioural components of students’ attitudes toward technology in a Swedish context, using the PATT-SQ-SE instrument including the Mitcham score open items. Results of the analyses show that relationships among the attitudinal components are observable. The results also imply that relationships among the attitudinal components are different for girls than boys. A key factor for the participating students’ attitudinal relations was interest (affective component) in technology education. An individual interest in technology education was related to both the cognitive component and behavioral intention. Another key relationship, for girls, was that the cognitive component had a strong relationship with behavioral intention, which was not the case for boys. Based on the observed relations between the cognitive, affective and behavioural components we have identified two key implications for educational practice: Girls should learn a broader conception of technology in technology education, if we want them to pursue technology-related careers to a higher degree; Students’ interest in technology should be stimulated through engaging tasks in technology education.

There is not one single global version of technology education; curricula and standards have different forms and content. This sometimes leads to difficulties in discussing and comparing technology education internationally. Existing philosophical frameworks of technological knowledge have not been used to any great extent in technology education. In response, the aim of this article is to construct a heuristic framework for technology education, based on professional and academic technological knowledge traditions. We present this framework as an epistemological tripod of technology education with mutually supporting legs. We discuss how this tripod relates to a selection of epistemological views within the philosophy of technology. Furthermore, we apply the framework to the Swedish and English technology curricula, to demonstrate its utility as an analytic tool when discerning differences between national curricula. Each leg of the tripod represents one category of technological knowledge: (1) technical skills, (2) technological scientific knowledge and (3) socio-ethical technical understanding. The heuristic framework is a conceptual model intended for use in discussing, describing, and comparing curriculum components and technology education in general, and potentially also as support for planning and conducting technology teaching. It may facilitate common understanding of technology education between different countries and technology education traditions. Furthermore, it is a potentially powerful tool for concretising the components of technological literacy.

Virtuella laborationer gör det möjligt för elever att labba utan att vara i en laborationssal. Men hur står sig digitala laborationer mot fysiska laborationer? Allt mer forskning undersöker detta, och resultaten visar att det är viktigt för lärare att ha tänkt igenom målet med laborationen för att kunna bedöma om en virtuell eller en fysisk laboration är lämplig.

Under tre terminer har hela utbildningsväsendet i Sverige varit hårt prövat av pandemin covid-19. Vi är fortfarande långt ifrån att kunna summera dess långsiktiga effekter. Utöver belastningen så har situationen också fört med sig nya sätt att arbeta, tänka och vara. Redaktionen för ATENA Didaktik vill med detta temanummer uppmärksamma och stödja det professionella lärande som under den senaste tiden har aktualiserats. I den här texten presenteras också hur skolan och forskning om undervisning har påverkats.

Public understanding of contemporary scientific issues is critical for the future of society. Public spaces, such as science centers, can impact the communication of science by providing active knowledge-building experiences of scientific phenomena. In contributing to this vision, we have previously developed an interactive visualization as part of a public exhibition about nano. We reflect on how the immersive design and features of the exhibit contribute as a tool for science communication in light of the emerging paradigm of exploranation, and offer some forward-looking perspectives about what this notion has to offer the domain. Funding agencies: Swedish Research Council (Vetenskapsradet)Swedish Research Council [2011-5569]; Norrkoping Visualization Center C (NVAB); NanoForm project organization

Future societal and economic impacts of nanoscience and nanotechnology raise the demand for a nano-literate public as well as a nano-competent workforce. This translates into the urgent need for nano education interventions in schools and informal learning contexts. In seeking to meet this mandate, we have developed and investigated a virtual reality environment that induces immersive presence (feeling as being ‘in’ the virtual world) and exploits bodily movements (e.g. hand gestures to control virtual objects) for students and citizens to learn nano concepts. In this article, we argue that such scientifically-informed immersive and interactive visualizations have a unique potential in communicating nanoscale ideas to students as well as the general public. Funding agencies: Swedish Research Council (Vetenskapsradet) [2011-5569] Swedish Research Council (Vetenskapsrådet, grant 2011-5569)

Välkommen till första numret av ATENA Didaktik - en digital, professionsvetenskaplig tidskrift om ämnesdidaktisk forskning inom de naturvetenskapliga ämnena och teknik. Tidskriften vänder sig till lärarprofessionen och forskare, och vår förhoppning är att den ska ge lärare bättre förutsättningar att bygga undervisning på vetenskaplig grund och beprövad erfarenhet. ATENA Didaktik – Avisa för Teknikens och Naturvetenskapernas Didaktik – lanserades den 17 oktober 2019 i samband med att de första artiklarna publicerades på atenadidaktik.se. Det är en digital, professionsvetenskaplig tidskrift som erbjuder en samlad och enkel väg till ämnesdidaktisk forskning inom de naturvetenskapliga ämnena och teknik. ATENA Didaktik fungerar också som ett forum där lärare kan dela med sig av sina erfarenheter som ett led i att dokumentera beprövad erfarenhet. Artiklarna som publiceras i tidskriften vänder sig i första hand till lärarprofessionen, det vill säga förskollärare, lärare i fritidshem, lärare i grundskolan, på gymnasieskolan och i vuxenutbildningen. Den vänder sig även till lärare med särskilda utvecklingsuppdrag inom exempelvis kommuner och myndigheter, men också till skolledare på alla nivåer. Dessutom riktar sig ATENA Didaktik till lärarstudenter, lärarutbildare och forskare på lärosäten.

Educational research on attitudes shows that both teaching and student learningare affected by the attitudes of the teacher. The aim of this study is to examine technologyteachers’ perceptions of and attitudes towards teaching technology in Swedish compulsoryschools, focusing on teachers’ perceived control. The following research question is posed:How do the teachers perceive self-efficacy and context dependency in teaching technology?Qualitative interviews were performed with 10 technology teachers in the compulsoryschool (ages 7–16), and the data was analysed using thematic analysis. Based on an attitudeframework, three sub-themes of self-efficacy were found: experience, education andinterest, subject knowledge, and preparation. Furthermore, four sub-themes of contextdependency were found; collegial support, syllabus, resources and status. The results showthat, according to the teachers in this study, self-efficacy mainly comes from experience,education and interest. Moreover, contextual factors can both limit and boost the teachers,but overall there are negative attitudes because of a lack of support and resources, whichimpedes the teaching. Teachers educated in technology education generally express morepositive attitudes and thus seem to have advantages in relation to technology teaching, butstill they sometimes express negative attitudes in the field of perceived control. Someimplications of this study are that it is necessary to promote teacher education in technologyand to reserve resources for technology education in schools, thereby supportingteachers in controlling contextual and internal factors that affect their teaching. Thissupport to teachers is especially important if there is an intention for the subject to developin new directions.

Antibiotic resistance is typically used to justify education about evolution, as evolutionary reasoning improves our understanding of causes of resistance and possible countermeasures. It has also been promoted as a useful context for teaching natural selection, because its potency as a selection factor, in combination with the very short generation times of bacteria, allows observation of rapid selection. It is also amenable to animations, which have potential for promoting conceptual inferences. Thus, we have explored the potential benefits of introducing antibiotic resistance as a first example of natural selection, in animations, to novice pupils (aged 13–14 years). We created a series of animations that pupils interacted with in groups of 3–5 (total n = 32). Data were collected at individual (pre-/post- test) and group (collaborative group questions) levels. In addition, the exercise was video-recorded and the full transcripts were analysed inductively. The results show that most of the pupils successfully applied basic evolutionary reasoning to predict antibiotic resistance development in tasks during and after the exercise, suggesting that this may be an effective approach. Pedagogical contributions include the identification of certain characteristics of the bacterial context for evolution teaching, including common misunderstandings, and factors to consider when designing animations. Funding agencies: Swedish Research Council (Vetenskapsradet) [2012-5344] EvoVis

The present study explores the extent and precision of evolutionary explanations for antibiotic resistance in communication directed toward the Swedish public. Bacterial resistance develops through evolutionary mechanisms and knowledge of these helps to explain causes underlying the growing prevalence of resistant strains, as well as important countermeasures to address the problem. A content analysis based on key evolutionary concepts underpinning resistance development was conducted on three different data sources: print newspapers, online websites and biology textbooks. The results revealed that evolutionary mechanisms are seldom included in accounts of antibiotic resistance provided by these sources. One of the included textbooks (n = 6) but none of the newspaper articles (n = 221) or websites (n = 19) covered all six concepts considered in the analysis. A cluster of four concepts regarded as most important for understanding the evolution of resistance development was only included in one news article...

Educational videos on the Internet comprise a vast and highly diverse source of information. Online search engines facilitate access to numerous videos claiming to explain natural selection, but little is known about the degree to which the video content match key evolutionary content identified as important in evolution education research. In this study, we therefore analyzed the content of 60 videos accessed through the Internet, using a criteria catalog with 38 operationalized variables derived from research literature. The variables were sorted into four categories: (a) key concepts (e.g. limited resources and inherited variation), (b) threshold concepts (abstract concepts with a transforming and integrative function), (c) misconceptions (e.g. that evolution is driven by need), and (d) organismal context (e.g. animal or plant). The results indicate that some concepts are frequently communicated, and certain taxa are commonly used to illustrate concepts, while others are seldom included. In addition, evolutionary phenomena at small temporal and spatial scales, such as subcellular processes, are rarely covered. Rather, the focus is on population-level events over time scales spanning years or longer. This is consistent with an observed lack of explanations regarding how randomly occurring mutations provide the basis for variation (and thus natural selection). The findings imply, among other things, that some components of natural selection warrant far more attention in biology teaching and science education research. EvoVis

Background: From previous research among science teachers itis known that teachers’ attitudes to their subjects affect important aspects of their teaching, including their confidence and the amount of time they spend teaching the subject. In contrast, less is known about technology teachers’ attitudes. Purpose: Therefore, the aim of this study is to investigate Swedish technology teachers’ attitudes toward their subject, and how these attitudes may be related to background variables. Sample: Technology teachers in Swedish compulsory schools(n = 1153) responded to a questionnaire about teachers’ attitudes,experiences, and background. Methods: Exploratory factor analysis was used to investigate attitude dimensions of the questionnaire. Groupings of teachers based on attitudes were identified through cluster analysis, and multinomial logistic regression was performed to investigate the role of teachers’ background variables as predictors for cluster belonging. Results: Four attitudinal dimensions were identified in the questionnaire, corresponding to distinct components of attitudes.Three teacher clusters were identified among the respondents characterized by positive, negative, and mixed attitudes toward the subject of technology and its teaching, respectively. The most influential predictors of cluster membership were to be qualified for teaching technology, having participated in in-service-training, teaching at a school with a proper overall teaching plan for the subject of technology and teaching at a school with a defined number of teaching hours for the subject. Conclusions: The results suggest that efforts to increase technology teachers’ qualifications and establishing a fixed number of teaching hours and an overall teaching plan for the subject of technology may yield more positive attitudes among teachers toward technology teaching. In turn, this could improve the status of the subject as well as students’ learning.

Learning to talk science is an important aspect of learning to do science. Given that scientists' language frequently includes intentions and purposes in explanations of unobservable objects and events, teachers must interpret whether learners' use of such language reflects a scientific understanding or inaccurate anthropomorphism and teleology. In the present study, a framework consisting of three 'stances' (Dennett, 1987) - intentional, design and physical - is presented as a powerful tool for analysing students' language use. The aim was to investigate how the framework can be differentiated and used analytically for interpreting students' talk about a molecular process. Semi-structured group discussions and individual interviews about the molecular self-assembly process were conducted with engineering biology/chemistry (n=15) and biology/chemistry teacher students (n=6). Qualitative content analysis of transcripts showed that all three stances were employed by students. The analysis also identified subcategories for each stance, and revealed that intentional language with respect to molecular movement and assumptions about design requirements may be potentially problematic areas. Students' exclusion of physical stance explanations may indicate literal anthropomorphic interpretations. Implications for practice include providing teachers with a tool for scaffolding their use of metaphorical language and for supporting students' metacognitive development as scientific language users. Funding agencies: Swedish Research Council (Vetenskapsradet) [2008-5077]

Purpose Transitioning to independence may be problematic for persons with spina bifida (SB). Experiences of young persons with SB may provide insights into this group's needs for support. Therefore, the aim of this study was to investigate children's and adolescents' experiences of living with SB, their social and emotional adjustment, and their thoughts about becoming independent adults. Method Semi-structured interviews were conducted with young persons with SB (N = 8, age range 10-17 years). Social and emotional problems were assessed using Beck Youth Inventories. The interview transcripts were analyzed using qualitative content analysis. Results Three main themes were found: being a person with SB; everyday living as a person with SB; and preparing for life as an adult with SB. Indications of emotional and social problems were most prominent among participants with milder physical disability. Conclusions The findings indicate that young persons with SB may overestimate their independence. Other potentially problematic areas were lack of motivation, planning and preparedness for becoming independent. Research on transition to independence in this group should consider assistance at an early age in planning and executing strategies for independence. In addition, the potentially difficult situation for young persons with mild SB should be investigated further. Implications for rehabilitation Children and adolescents with spina bifida might lack the motivation and skills for planning their future and health care programmes should therefore include preparations for life as an adult. Clinical assessment of the level of independence should specifically distinguish between the activities they know how to do and what tasks they actually execute independently. Routine follow-ups should include screening for problems with social and emotional adjustment. Be aware of a potential condition-severity paradox whereby those with less severe impairment might have an increased risk of developing symptoms of social and emotional problems.

Visualizing molecular properties is often crucial for constructing conceptual understanding in chemistry. However, research has revealed numerous challenges surrounding students’ meaningful interpretation of the relationship between the geometry and electrostatic properties of molecules. This study explored students’ (n = 18) use of three visual representations of electrostatic potential to interpret whether molecules are polar or nonpolar. The representations consisted of red and blue “lobes” (termed RB) indicating regions of negative and positive potential, a color gradient mapping electrostatic potential on a molecular surface (MAP), and a rendering of the interface between regions of positive and negative potential (ISO). Data on students’ accuracy, time-on-task, and evaluation related to the three visual modes were collected via a Web-based questionnaire. ANOVA indicated that students were significantly more accurate in interpreting ISO representations, although almost half evaluated this mode as the...

The advent of nanoscientific applications in modern life is swiftly in progress. Nanoscale innovation comes with the pressing need to provide citizens and learners with scientific knowledge for judging the societal impact of nanotechnology. In rising to the challenge, this paper reports the developmental phase of a research agenda concerned with building and investigating a virtual environment for communicating nano-ideas. Methods involved elucidating core nano-principles through two purposefully contrasting nano “risk” and “benefit” scenarios for incorporation into an immersive system. The authors implemented the resulting 3D virtual architecture through an exploration of citizens' and school students' interaction with the virtual nanoworld. Findings suggest that users' interactive experiences of conducting the two tasks based on gestural interaction with the system serve as a cognitive gateway for engendering nano-related understanding underpinning perceived hopes and fears and as a stimulating pedagogical basis from which to teach complex science concepts.

Nano education involves tackling the difficult task of conceptualizing imperceptibly small objects and processes. Interactive visualization serves as one potential solution for providing access to the nanoworld through active exploration of nanoscale concepts and principles. This chapter exposes and describes a selection of interactive visualizations in the literature, and reviews research findings related to their educational, perceptual and cognitive influence. In closing, we offer implications of interactive visualization for learning and teaching nano.

As the application of nanotechnology in everyday life impacts society, it becomes critical for citizens to have a scientific basis upon which to judge their perceived hopes and fears of ‘nano’. Although multiple instruments have been designed for assessing attitudinal and affective aspects of nano, surprisingly little work has focused on developing tools to evaluate the conceptual knowledge dimension of public understanding. This article reports the validation of an instrument designed to measure conceptual knowledge of nanoscience and nanotechnology. A sample of 302 participants responded to a 28-item questionnaire designed around core nano-concepts. Factor analysis revealed a single latent variable representing the construct of nano-knowledge. Cronbach's alpha was 0.91 indicating a high internal consistency of the questionnaire items. The mean test score was 15.3 out of 28 (54.5%) with item difficulty indices ranging from 0.19 to 0.89. Obtained item discrimination values indicate a high discriminatory power of the instrument. Taken together, the psychometric properties of the Nano-Knowledge Instrument (NanoKI) suggest that it is a valid and reliable tool for measuring nano-related knowledge. Preliminary qualitative observations of citizens' incorrect and correct response patterns to the questionnaire indicate potential conceptual challenges surrounding relative size of the nanoscale, random motion of nano-objects, and nanoscale interactions, although these are hypotheses that require future investigation. Application of the NanoKI could support efforts directed to an agenda for evaluating and designing science communication and education initiatives for promoting understanding of nano. NanoSim

Antibiotic resistance is an increasing global threat involving many actors, including the general public. We present findings from a content analysis of the coverage of antibiotic resistance in the Swedish print media with respect to the risk communication factors cause, magnitude and countermeasures. The most commonly reported cause of development and spread of resistance was unnecessary prescription of antibiotics. Risk magnitudes were mostly reported qualitatively rather than using quantitative figures. Risk-reduction measures were analyzed using a framework that distinguishes between personal and societal efficacy. Measures at the societal level were more commonly reported compared to the individual level.

This study found that external representations can support university students' learning in a group discussion about the counterintuitive concept of biomolecular self-assembly. In addition, qualitative differences indicated that the tangible model was particularly well-suited to support learning of dynamic aspects compared with the static image., Self-assembly is the fundamental but counterintuitive principle that explains how ordered biomolecular complexes form spontaneously in the cell. This study investigated the impact of using two external representations of virus self-assembly, an interactive tangible three-dimensional model and a static two-dimensional image, on student learning about the process of self-assembly in a group exercise. A conceptual analysis of self-assembly into a set of facets was performed to support study design and analysis. Written responses were collected in a pretest/posttest experimental design with 32 Swedish university students. A quantitative analysis of close-ended items indicated that the students improved their scores between pretest and posttest, with no significant difference between the conditions (tangible model/image). A qualitative analysis of an open-ended item indicated students were unfamiliar with self-assembly prior to the study. Students in the tangible model condition used the facets of self-assembly in their open-ended posttest responses more frequently than students in the image condition. In particular, it appears that the dynamic properties of the tangible model may support student understanding of self-assembly in terms of the random and reversible nature of molecular interactions. A tentative difference was observed in response complexity, with more multifaceted responses in the tangible model condition.

Recent educational research has suggested that immersive multisensory virtual environments offer learners unique and exciting knowledge-building opportunities for the construction of scientific knowledge. This paper delivers a case-based study of students’ immersive interaction with electric fields around molecules in a multisensory visuohaptic virtual environment. The virtual architecture presented here also has conceptual connections to the flourishing quest in contemporary literature for the pressing need to communicate nanoscientific ideas to learners. Five upper secondary school students’ prior conceptual understanding of electric fields and their application of this knowledge to molecular contexts, were probed prior to exposure to the virtual model. Subsequently, four students interacted with the visuohaptic model while performing think-aloud tasks. An inductive and heuristic treatment of videotaped verbal and behavioural data revealed distinct interrelationships between students’ interactive strategies implemented when executing tasks in the virtual system and the nature of their conceptual knowledge deployed. The obtained qualitative case study evidence could serve as an empirical basis for informing the rendering and communication of overarching nanoscale ideas. At the time of composing this paper for publication in the current journal, the research findings of this study have been put into motion in informing a broader project goal of developing educational virtual environments for depicting nanophenomena.

Swift scientific advances in the area of nanoscience suggest that nanotechnology will play an increasingly important role in our everyday lives. Thus, knowledge of the principles underlying such technologies will inevitably be required to ensure a skilled industrial workforce. In this paper we describe the development of a virtual educational environment that allows for various direct interactive experiences and communication of nanophenomena to pupils and citizens, ranging from desktops to immersive and multi-sensory platforms. At the heart of the architecture is a nanoparticle simulator, which simulates effects such as short-range interaction, flexing of nanotubes and collisions with the solvent. The environment allows the user to interact with the particles to examine their behaviour related to fundamental science concepts.

Machine metaphors are ubiquitous in the molecular sciences. In addition to their use by scientists, educators and popularizers of science, they have been promoted intensively by the Intelligent Design (ID) movement in arguments for the necessity of a god-like designer to account for the complexities of life at the molecular level. The authors have investigated the visual rhetoric employed in a movie by ID proponents, with particular emphasis on machine metaphors. The authors provide examples and argue that science communicators could reduce the persuasive impact of ID visual rhetoric based on machine metaphors by emphasizing that self-assembly is fundamental to molecular complexes.

In this paper we present a history dependent transfer function (HDTF) as a possible approach to enable improved haptic feature detection in high dynamic range (HDR) volume data. The HDTF is a multi-dimensional transfer function that uses the recent force history as a selection criterion to switch between transfer functions, thereby adapting to the explored force range. The HDTF has been evaluated using artificial test data and in a realistic application example, with the HDTF applied to haptic protein-ligand docking. Biochemistry experts performed docking tests, and expressed that the HDTF delivers the expected feedback across a large force magnitude range, conveying both weak attractive and strong repulsive protein-ligand interaction forces. Feature detection tests have been performed with positive results, indicating that the HDTF improves the ability of feature detection in HDR volume data as compared to a static transfer function covering the same range. ©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Petter Bivall Persson, Gunnar E. Höst, Matthew D. Cooper, Lena A. E. Tibell and Anders Ynnerman, Improved Feature Detection over Large Force Ranges Using History Dependent Transfer Functions, 2009, Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environments and Teleoperator Systems, WorldHaptics 2009, 476-481. http://dx.doi.org/10.1109/WHC.2009.4810843 VisMolLS

Enzymes capable of benzoate ester hydrolysis have several potential medical and industrial applications. A variant of human carbonic anhydrase II (HCAII) was constructed, by rational design, that is capable of hydrolysing para-nitrophenyl benzoate (pNPBenzo) with an efficiency comparable to some naturally occuring esterases. The design was based on a previously developed strategy,[1] in which docking of a transition state analogue (TSA) to the active site of HCAII was used to predict mutations that would allow the reaction. A triple mutant, V121A/V143A/T200A, was thus constructed and shown to hydrolyze pNPBenzo with kcat/KM = 625 (± 38) M-1s-1. It is highly active with other ester substrates as well, and hydrolyzes para-nitrophenyl acetate with kcat/KM = 101700 (± 4800) M-1s-1, which is the highest esterase efficiency so far for any CA variant. A parent mutant (V121A/V143A) has measurable KM values for para-nitrophenyl butyrate (pNPB) and valerate (pNPV),[1] but for V121A/V143A/T200A no KM could be determined, showing that the additional T200A mutation has caused a decreased substrate binding. However, kcat/KM is higher with both substrates for the triple mutant, indicating that binding energy has been diverted from substrate binding to transition state stabilization. Original publication: Gunnar E. Höst and Bengt-Harald Jonsson, Converting human carbonic anhydrase II into a benzoate ester hydrolase through rational redesign, 2008, Biochimica et Biophysica Acta, (1784), 5, 811-815. http://dx.doi.org/10.1016/j.bbapap.2008.02.007. Copyright: Elsevier B.V., http://www.elsevier.com/

A histidine-based, two-residue reactive site for the catalysis of hydrolysis of designed sulfonamide-containing para-nitrophenyl esters has been engineered into a scaffold protein. A matching substrate was designed to exploit the natural active site of human carbonic anhydrase II (HCAII) for well-defined binding. In this we took advantage of the high affinity between the active site zinc atom and sulfonamides. The ester substrate was designed to position the scissile bond in close proximity to the His64 residue in the scaffold protein. Three potential sites for grafting the catalytic His-His pair were identified, and the corresponding N62H/H64, F131H/V135H and L198H/P202H mutants were constructed. The most efficient variant, F131H/V135H, has a maximum k(cat)/K(M) value of approximately 14 000 M(-1) s(-1), with a k(cat) value that is increased by a factor of 3 relative to that of the wild-type HCAII, and by a factor of over 13 relative to the H64A mutant. The results show that an esterase can be designed in a stepwise way by a combination of substrate design and grafting of a designed catalytic motif into a well-defined substrate binding site.

The effect of modulating the shape and the size of the hydrophobic pocket on the esterase activity and specificity of human carbonic anhydrase II (HCAII) for esters with different acyl chain lengths was investigated. Following an initial screen of 7 HCAII variants with alanine substitutions in positions 121, 143 and 198, detailed kinetic measurements were performed on HCAII and the variants V121A, V143A and V121A/V143A. For some variants, an increased size of the hydrophobic pocket resulted in increased activities and specificities for longer substrates. For V121A/V143A, the rate of hydrolysis for paranitrophenyl valerate was increased by a factor of approximately 3000. The specificities also changed dramatically, for example V121A/V143A is 6.3 times more efficient with paranitrophenyl valerate than paranitrophenyl acetate, while HCAII is > 500 times more efficient with paranitrophenyl acetate than paranitrophenyl valerate. An automated docking procedure was performed on these variants with transition state analogues (TSAs) for the hydrolysis reaction. It was possible to correlate the catalytic rate constants to the docking results, i.e. for each variant, efficient hydrolysis was generally correlated to successful TSA-docking. The observations in this paper show that the redesign increased the catalytic rates for substrates with long acyl chains by removal of steric hinders and addition of new favourable binding interactions. Original Publication:Gunnar Höst, Lars-Göran Mårtensson and Bengt-Harald Jonsson, Redesign of human carbonic anhydrase II for increased esterase activity and specificity towards esters with long acyl chains, 2006, Biochimica et Biophysica Acta (BBA) - Proteins & Proteomics, (1764), 10, 1601-1606.http://dx.doi.org/10.1016/j.bbapap.2006.07.010Copyright: Elsevierhttp://www.elsevier.com/

To help in interpreting the polarity of a molecule, charge separation can be visualized by mapping the electrostatic potential at the van der Waals surface using a color gradient or by indicating positive and negative regions of the electrostatic potential using different colored isosurfaces. Although these visualizations capture the molecular charge distribution efficiently, using them to deduce overall polarity requires students to engage in the potentially demanding process of interpreting the relative positions of electron-rich and electron-poor areas. We present a visual tool that could help students assign polarity by exploiting the unique topography of the interface between negative and positive regions of electrostatic potential surrounding a molecule. Specifically, the tool renders the electrostatic potential isosurface(s) of a molecule obtained when the isovalue is set at 0. Examples of polar and nonpolar molecules are discussed.