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Solution-state NMR can be used to study protein- lipid interactions, in particular, the effect that proteins have on lipids. One drawback is that only small assemblies can be studied, and therefore, fast-tumbling bicelles are commonly used. Bicelles contain a lipid bilayer that is solubilized by detergents. A complication is that they are only stable at high concentrations, exceeding the CMC of the detergent. This issue has previously been addressed by introducing a detergent (Cyclosfos-6) with a substantially lower CMC. Here, we developed a set of bicelles using this detergent for studies of membrane-associated mycobacterial proteins, for example, PimA, a key enzyme for bacterial growth. To mimic the lipid composition of mycobacterial membranes, PI, PG, and PC lipids were used. Diffusion NMR was used to characterize the bicelles, and spin relaxation was used to measure the dynamic properties of the lipids. The results suggest that bicelles are formed, although they are smaller than conventional bicelles. Moreover, we studied the effect of MTSL-labeled PimA on bicelles containing PI and PC. The paramagnetic label was shown to have a shallow location in the bicelle, affecting the glycerol backbone of the lipids. We foresee that these bicelles will be useful for detailed studies of protein-lipid interactions.

Solution-state NMR can be used to study protein–lipid interactions, in particular, the effect that proteins have on lipids. One drawback is that only small assemblies can be studied, and therefore, fast-tumbling bicelles are commonly used. Bicelles contain a lipid bilayer that is solubilized by detergents. A complication is that they are only stable at high concentrations, exceeding the CMC of the detergent. This issue has previously been addressed by introducing a detergent (Cyclosfos-6) with a substantially lower CMC. Here, we developed a set of bicelles using this detergent for studies of membrane-associated mycobacterial proteins, for example, PimA, a key enzyme for bacterial growth. To mimic the lipid composition of mycobacterial membranes, PI, PG, and PC lipids were used. Diffusion NMR was used to characterize the bicelles, and spin relaxation was used to measure the dynamic properties of the lipids. The results suggest that bicelles are formed, although they are smaller than “conventional” bicelles. Moreover, we studied the effect of MTSL-labeled PimA on bicelles containing PI and PC. The paramagnetic label was shown to have a shallow location in the bicelle, affecting the glycerol backbone of the lipids. We foresee that these bicelles will be useful for detailed studies of protein–lipid interactions.

The twin-arginine translocase (Tat) mediates the transport of already-folded proteins across membranes in bacteria, plants and archaea. TatA is a small, dynamic subunit of the Tat-system that is believed to be the active component during target protein translocation. TatA is foremost characterized as a bitopic membrane protein, but has also been found to partition into a soluble, oligomeric structure of yet unknown function. To elucidate the interplay between the membrane-bound and soluble forms we have investigated the oligomers formed by Arabidopsis thaliana TatA. We used several biophysical techniques to study the oligomeric structure in solution, the conversion that takes place upon interaction with membrane models of different compositions, and the effect on bilayer integrity upon insertion. Our results demonstrate that in solution TatA oligomerizes into large objects with a high degree of ordered structure. Upon interaction with lipids, conformational changes take place and TatA disintegrates into lower order oligomers. The insertion of TatA into lipid bilayers causes a temporary leakage of small molecules across the bilayer. The disruptive effect on the membrane is dependent on the liposome's negative surface charge density, with more leakage observed for purely zwitterionic bilayers. Overall, our findings indicate that A. thaliana TatA forms oligomers in solution that insert into bilayers, a process that involves reorganization of the protein oligomer., QC 20210126

Background: Sport has been traditionally characterised for its possibilities for enjoyment and the opportunities that provides for democracy and inclusion. However, there have been many challenges lately given the binary gender categories that people need to participate in. That binary system causes problems for the inclusion of individuals who do not fit in either of those binary categories, like transgender people. Purpose: This study aims to explore the challenges that transgender people face when participating in sport. Methods: A literature review comprising 20 articles has been conducted. The articles included were retrieved from different databases, such as Google Scholar, PsycINFO, Sportdiscus, Semanticscholar, Scopus and Web of Science. Some manual searches were also conducted. Findings: The results show that transgender people face a numerous obstacle when trying to participate in sports. The main findings were classified into four major categories: 1. social aspects, 2. content of activities, 3. locker rooms, body appearance and clothing, and 4. physiological aspects. Conclusion: The findings of this study suggest that the binary gender categorisation in sports is a major obstacle for transgender people to be (and feel) included in sports.

The Saccharomyces cerevisiae respiratory supercomplex factor 2 (Rcf2) is a 224-residue protein located in the mitochondrial inner membrane where it is involved in the formation of supercomplexes composed of cytochrome bc(1) and cytochrome c oxidase. We previously demonstrated that Rcf2 forms a dimer in dodecylphosphocholine micelles, and here we report the solution NMR structure of this Rcf2 dimer. Each Rcf2 monomer has two soluble alpha helices and five putative transmembrane (TM) alpha helices, including an unexpectedly charged TM helix at the C terminus, which mediates dimer formation. The NOE contacts indicate the presence of inter-monomer salt bridges and hydrogen bonds at the dimer interface, which stabilize the Rcf2 dimer structure. Moreover, NMR chemical shift change mapping upon lipid titrations as well as molecular dynamics analysis reveal possible structural changes upon embedding Rcf2 into a native lipid environment. Our results contribute to the understanding of respiratory supercomplex formation and regulation.

Density functional theory calculations were used to establish correlations between the structure and the vibrational spectrum of the phosphate group in model compounds for phosphorylated amino acids. The model compounds were acetyl phosphate, methyl phosphate, and p-tolyl phosphate, which represented the phosphorylated amino acids aspartyl phosphate, serine or threonine phosphate, and tyrosine phosphate, respectively. The compounds were placed in different environments consisting of one or several HF or H2O molecules, which modeled interactions of phosphorylated amino acids in the protein environment. The calculations were performed with the B3LYP functional and the 6-311++G(3df, 3pd) basis set. In general, the wavenumbers (or frequencies) of the stretching vibrations of the terminal P-O bonds correlated better with bond lengths of the phosphate group than with its bond angles. The best correlations were obtained with the shortest and the mean terminal P-O bond lengths with standard deviations from the trend line of only 0.2 pm. Other useful correlations were observed with the bond length difference between the shortest and longest terminal P-O bond and with the bond length of the bridging P-O bond.

The Saccharomyces cerevisiae mitochondrial respiratory supercomplex factor2 (Rcf2) plays a role in assembly of supercomplexes composed of cytochromebc(1) (complexIII) and cytochromec oxidase (complexIV). We expressed the Rcf2 protein in Escherichia coli, refolded it, and reconstituted it into dodecylphosphocholine (DPC) micelles. The structural properties of Rcf2 were studied by solution NMR, and near complete backbone assignment of Rcf2 was achieved. The secondary structure of Rcf2 contains seven helices, of which five are putative transmembrane (TM) helices, including, unexpectedly, a region formed by a charged 20-residue helix at the Cterminus. Further studies demonstrated that Rcf2 forms a dimer, and the charged TM helix is involved in this dimer formation. Our results provide a basis for understanding the role of this assembly/regulatory factor in supercomplex formation and function.

The twin-arginine translocase (Tat) transports folded proteins across the cytoplasmic membrane of prokaryotes and the thylakoid membrane of plant chloroplasts. In Gram-negative bacteria and chloroplasts, the translocon consists of three subunits, TatA, TatB, and TatC, of which TatA is responsible for the actual membrane translocation of the substrate. Herein we report on the structure, dynamics, and lipid interactions of a fully functional C-terminally truncated core TatA' from Arabidopsisthaliana using solution-state NMR. Our results show that TatA consists of a short N-terminal transmembrane helix (TMH), a short connecting linker (hinge) and a long region with propensity to form an amphiphilic helix (APH). The dynamics of TatA were characterized using N-15 relaxation NMR in combination with model-free analysis. The TMH has order parameters characteristic of a well-structured helix, the hinge is somewhat less rigid, while the APH has lower order parameters indicating structural flexibility. The TMH is short with a surprisingly low protection from solvent, and only the first part of the APH is protected to some extent. In order to uncover possible differences in TatA's structure and dynamics in detergent compared to in a lipid bilayer, fast-tumbling bicelles and large unilamellar vesicles were used. Results indicate that the helicity of TatA increases in both the TMH and APH in the presence of lipids, and that the N-terminal part of the TMH is significantly more rigid. The results indicate that plant TatA has a significant structural plasticity and a capability to adapt to local environments.

Solution-state NMR requires small membrane mimetic systems to allow for acquiring high-resolution data. At the same time these mimetics should faithfully mimic biological membranes. Here we characterized two novel fast-tumbling bicelle systems with lipids from two Escherichia coli strains. While strain 1 (AD93WT) contains a characteristic E. coli lipid composition, strain 2 (AD93-PE) is not capable of synthesizing the most abundant lipid in E. coli, phosphatidylethanolamine. The lipid and acyl chain compositions were characterized by P-31 and C-13 NMR. Depending on growth temperature and phase, the lipid composition varies substantially, which means that the bicelle composition can be tuned by using lipids from cells grown at different temperatures and growth phases. The hydrodynamic radii of the bicelles were determined from translational diffusion coefficients and NMR spin relaxation was measured to investigate lipid properties in the bicelles. We find that the lipid dynamics are unaffected by variations in lipid composition, suggesting that the bilayer is in a fluid phase under all conditions investigated here. Backbone glycerol carbons are the most rigid positions in all lipids, while head-group carbons and the first carbons of the acyl chain are somewhat more flexible. The flexibility increases down the acyl chain to almost unrestricted motion at its end. Carbons in double bonds and cyclopropane moieties are substantially restricted in their motional freedom. The bicelle systems characterized here are thus found to faithfully mimic E. coli inner membranes and are therefore useful for membrane interaction studies of proteins with E. coli inner membranes by solution-state NMR.

The glycosyltransferase WaaG is involved in the synthesis of lipopolysaccharides that constitute the outer leaflet of the outer membrane in Gram-negative bacteria such as Escherichia coli. WaaG has been identified as a potential antibiotic target, and inhibitor scaffolds have previously been investigated. WaaG is located at the cytosolic side of the inner membrane, where the enzyme catalyzes the transfer of the first outer-core glucose to the inner core of nascent lipopolysaccharides. Here, we characterized the binding of WaaG to membrane models designed to mimic the inner membrane of E. coli. Based on the crystal structure, we identified an exposed and largely a-helical 30-residue sequence, with a net positive charge and several aromatic amino acids, as a putative membrane-interacting region of WaaG (MIR-WaaG). We studied the peptide corresponding to this sequence, along with its bilayer interactions, using circular dichroism, fluorescence quenching, fluorescence anisotropy, and NMR. In the presence of dodecylphosphocholine, MIR-WaaG was observed to adopt a three-dimensional structure remarkably similar to the segment in the crystal structure. We found that the membrane interaction of WaaG is conferred at least in part by MIR-WaaG and that electrostatic interactions play a key role in binding. Moreover, we propose a mechanism of anchoring WaaG to the inner membrane of E. coli, where the central part of MIR-WaaG inserts into one leaflet of the bilayer. In this model, electrostatic interactions as well as surface-exposed Tyr residues bind WaaG to the membrane.

Bakgrund: Utvecklingen av digitala verktyg som lärplattor och dess plats i skolan har medfört nya praktiker för lärare och elever. Bagga-Gupta (2013) menar att vi idag inte kan tala om praktiker för literacy utan att ta hänsyn till de digitala verktygen. Dessa verktyg finns överallt i vårt samhälle och präglar hur vi kommunicerar och söker information. Det väcker intressanta frågor att ställa sig. Hur påverkas förskoleklassens verksamhet och hur påverkas diskurserna kring barns skriftspråksutveckling? För oss var det således relevant att undersöka förskollärares syn på kopplingen mellan literacylärandet och lärplattor. Den svenskproducerade språkapplikationen Kul med Duffton har haft en central plats i studien.Syfte: Syftet är att undersöka förskollärares föreställningar om hur skriftspråksundervisningen påverkas när språkapplikationer till lärplattor introduceras i undervisningen, samt vilka konsekvenser det får för barns skriftspråksutveckling.Metod: Vi har genomfört en kvalitativ studie där fem förskollärare som är verksamma inom skolmiljö har intervjuats genom en fokusgrupp. En specialpedagog som deltagit i utvecklingen av Kul med Duffton intervjuades genom en halvstrukturerad intervju. Våra intervjuer har dokumenterats med ljudupptagning och transkriberats. Olika teman som identifierades blev utgångspunkt för analys.Resultat: Vår studie har visat att förskollärarna i studien ser lärplattan som ett verktyg med möjligheter och potential inom skriftspråksundervisningen. Förskollärarna påpekade emellertid att det innebär flera utmaningar att etablera lärplattan i skriftspråksundervisningen. De uttryckte en önskan att applikationerna bör vara anpassningsbara för att fungera bra för individanpassad undervisning. Tillgången till endast en lärplatta utgör ett hinder för att verktyget ska kunna ta plats i deras skriftspråksundervisning. Andra utmaningar som lyftes är att lärplattan är för många fortfarande ett nytt verktyg och det skulle krävas planeringstid för att bek

This study aims to gain greater knowledge about the phenomenon cheerleading journalism and its existence in the Swedish sports journalism. We did this by making an impact in the media debate, to thereby identify key aspects of cheerleading journalism. These elements are then used to reach a preliminary definition of the phenomenon. This was followed by qualitative interviews with six Swedish sports journalists from newspapers Aftonbladet and Dagens Nyheter, with the aim to find out how they behaved the phenomenon. The results of the earlier debate and the answers from the respondents show that cheerleading journalism is nationalistic, biased and seeks an inclusive effect on its audience. This phenomenon is considered to be an inferior form of journalism and progress especially in reporting on the Swedish national teams and / or individual representatives of Sweden. The results have also been related to selected theories, agenda-setting, gatekeeping and framing.

The purpose of this paper was to examine how the intervention "Conversational-contact with the social services" actually looks and how it is experienced by the youths who attend it and the social workers who are providing it. The research was based on a qualitative method consisting of individual interviews. Main issues of the paper: - The youths- and social workers' experience of the intervention - The youths' experience of being able to be open with the social worker - The youths' and social workers- experience of changes, as a result of the intervention - The youths and social workers ideas of improving the intervention - Content of the meetings that constitutes the intervention - For the purpose, functional theories and methods that the social workers use according to themselves The youths were more positive to the intervention than the social workers and believed that they are less likely to commit crime again, mainly because of the conversational-contact. The social workers believed that they lack competence, but the results indicates that they include several relevant factors in the intervention. The intervention is more supported by theory and method than what could be expected from previous research.

The organization of mitochondrial respiratory chain complexes into supercomplexes is vital to cellular activities. In the yeast Saccharomyces cerevisiae, Cox13 is a conserved peripheral subunit of complex IV (cytochrome c oxidase, CytcO) involved in the assembly of monomeric complex IV into supercomplexes. Here we report the solution NMR structure of a Cox13 dimer in detergent micelles. Each Cox13 monomer has three short flexible helices (SH), corresponding to the disordered regions in its homologous X-ray structure, and the dimer formation is mainly induced by the hydrophobic interaction between the sole transmembrane (TM) helix of each monomer. Furthermore, analysis of chemical shift changes upon addition of ATP reveal positions that are able to bind ATP at the conserved sites of the C-terminus with considerable conformational flexibility. From functional analysis of purified CytcO, we conclude that this ATP interaction is inhibitory of catalytic activity. Our results show the structure of an important subunit of yeast CytcO and provide structure-based insight into its ATP interaction.