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A study employs the X-ray crystallography technique to analyze the high-resolution crystal structure of a plant carboxylesterase, named Actinidia eriantha (AeCXEI), which is found to be closely related to the hormone-sensitive lipase subgroup structurally. The analysis reveals that the compound binds with paraoxon very easily forming a complex without inducing any change in the structure of the enzyme and hence helps in studying the role of carboxylesterases in plants.

Introduction: Identifying the most effective ways to support career development of early stage investigators in clinical and translational science should yield benefits for the biomedical research community. Institutions with Clinical and Translational Science Awards (CTSA) offer KL2 programs to facilitate career development; however, the sustained impact has not been widely assessed. Methods: A survey comprised of quantitative and qualitative questions was sent to 2144 individuals that had previously received support through CTSA KL2 mechanisms. The 547 responses were analyzed with identifying information redacted. Results: Respondents held MD (47%), PhD (36%), and MD/PhD (13%) degrees. After KL2 support was completed, physicians' time was divided 50% to research and 30% to patient care, whereas PhD respondents devoted 70% time to research. Funded research effort averaged 60% for the cohort. Respondents were satisfied with their career progression. More than 95% thought their current job was meaningful. Two-thirds felt confident or very confident in their ability to sustain a career in clinical and translational research. Factors cited as contributing to career success included protected time, mentoring, and collaborations. Conclusion: This first large systematic survey of KL2 alumni provides valuable insight into the group's perceptions of the program and outcome information. Former scholars are largely satisfied with their career choice and direction, national recognition of their expertise, and impact of their work. Importantly, they identified training activities that contributed to success. Our results and future analysis of the survey data should inform the framework for developing platforms to launch sustaining careers of translational scientists. [ABSTRACT FROM AUTHOR]

Research has been conducted on the proteins of the transferrin family. The role of these proteins in the iron homeostasis in vertebrates has been investigated and discussed.

Crystal structure analysis of the N-lobe half-molecule of human transferrin, which mediates iron transport, reveals a highly conserved iron binding site and hydrogen bonding interaction. Data point out that the binding and release of iron is influenced by the dilysine interaction.

Background and Introduction During the past 10 years, statistical analysis of ground water quality monitoring data from solid and hazardous waste disposal facilities has become routine. The goal of such [...]

X-ray diffraction studies were conducted to determine the structure of the trigonal crystal form of the beta-lactoglobulin of cows to determine the structural basis of the Tanford transition of this protein. Results of the studies done at different pH levels reveal that conformational changes in the segment spanning amino acid residues 85 to 90 is responsible for the physical and spectroscopic phenomena comprising the Tanford transition of beta-lactoglobulin.

The crystalline structures of the iron-bound, recombinant N-lobe of human serum transferrin has been studied at resolutions 1.6 and 1.8 angstroms. Transferrins are bilobal proteins that bind strongly with ferric iron at two similar binding sites. Both structures have folding patterns that resemble those of previously discovered transferrin and lactoferrin N-lobe structures. Its amino acid sequence has a polypeptide chain that has similar amino- and carboxyl-terminal halves.

Structural and spectral perturbations are seen when oxalate ion is substituted at the binding site for carbonate ion, in lactoferrin protein that belongs to the family of transferrin proteins. However, polypeptide folding and domain closure remain unaffected by the substitution. Oxalate is bound to iron at the C-lobe site of the bilobal transferrin in a symmetric 1,2-bidentate manner, whereas at the N-lobe site, the binding is asymmetric. This happens because oxalate, being a larger anion, displaces the wall forming arginine at the anion binding site.

JOAN ARUZ, KIM BENZEL & JEAN M. EVANS (ed.). Beyond Babylon: art, trade, and diplomacy in the second millennium BC. xxiv+524 pages, 460 b&w & colour illustrations. 2008. New Haven [...]

The binding of copper(II) instead of iron(III) to lactoferrin takes on a different coordination geometry but results in the same protein structure. The substitution, with subsequent crystal structure study, is undertaken to determine the effects of non-Fe metal binding to transferrins. Whereas the two binding sites for iron are the same, copper binds at the N-terminal site via a square pyramidal form and at the C-terminal site with a distorted octahedral. The difference results from the movement of metal ion andanion at each binding site but does not affect the protein structure.

Physicochemical and crystallographic studiesreveal the binding behavior of lactoferrin (Lf) to iron(III) and copper(II). Lfis a glycoprotein that easily binds with iron in biological fluids and thus controls its presence therein. The studies show that binding is done through the carbonate (CO3) anion which locks in bidentate fashion to the metal. Oxalate (C2O4) ions can displace one or both CO3 in a Lf-Cu(II) complex but notin a Lf-Fe(III) complex. In the hybrid (CO3-C2O4) complex, which results when alittle EDTA is present, the CO3 binds specifically at the C-lobe, displacing nearby side chains. A generalized model for anion binding is developed from these results.

Abstract Background The recently approved anti-AIDS drug rilpivirine (TMC278, Edurant) is a nonnucleoside inhibitor (NNRTI) that binds to reverse transcriptase (RT) and allosterically blocks the chemical step of DNA synthesis. In contrast to earlier NNRTIs, rilpivirine retains potency against well-characterized, clinically relevant RT mutants. Many structural analogues of rilpivirine are described in the patent literature, but detailed analyses of their antiviral activities have not been published. This work addresses the ability of several of these analogues to inhibit the replication of wild-type (WT) and drug-resistant HIV-1. Results We used a combination of structure activity relationships and X-ray crystallography to examine NNRTIs that are structurally related to rilpivirine to determine their ability to inhibit WT RT and several clinically relevant RT mutants. Several analogues showed broad activity with only modest losses of potency when challenged with drug-resistant viruses. Structural analyses (crystallography or modeling) of several analogues whose potencies were reduced by RT mutations provide insight into why these compounds were less effective. Conclusions Subtle variations between compounds can lead to profound differences in their activities and resistance profiles. Compounds with larger substitutions replacing the pyrimidine and benzonitrile groups of rilpivirine, which reorient pocket residues, tend to lose more activity against the mutants we tested. These results provide a deeper understanding of how rilpivirine and related compounds interact with the NNRTI binding pocket and should facilitate development of novel inhibitors.

Abstract Background Primary human tissues are an invaluable widely used tool for discovery of gene expression patterns which characterize disease states. Tissue processing methods remain unstandardized, leading to unanswered concerns of how to best store collected tissues and maintain reproducibility between laboratories. We subdivided uterine myometrial tissue specimens and stored split aliquots using the most common tissue processing methods (fresh, frozen, RNALater) before comparing quantitative RNA expression profiles on the Affymetrix U133 human expression array. Split samples and inclusion of duplicates within each processing group allowed us to undertake a formal genome-wide analysis comparing the magnitude of result variation contributed by sample source (different patients), processing protocol (fresh vs. frozen vs. 24 or 72 hours RNALater), and random background (duplicates). The dataset was randomly permuted to define a baseline pattern of ANOVA test statistic values against which the observed results could be interpreted. Results 14,639 of 22,283 genes were expressed in at least one sample. Patient subjects provided the greatest sources of variation in the mixed model ANOVA, with replicates and processing method the least. The magnitude of variation conferred by processing method (24 hours RNALater vs 72 hours RNALater vs. fresh vs frozen) was similar to the variability seen within replicates. Subset analysis of the test statistic according to gene functional class showed that the frequency of "outlier" ANOVA results within each functional class is overall no greater than expected by chance. Conclusions Ambient storage of tissues for 24 or 72 hours in RNALater did not contribute any systematic shift in quantitative RNA expression results relative to the alternatives of fresh or frozen tissue. This nontoxic preservative enables decentralized tissue collection for expression array analysis without a requirement for specialized equipment.

The crystal structure characterization of lipoprotein MtsA, a component of the MtsABC transporter of Streptococcus pyogenes to understand the bacterial metal binding receptor (MBR) fold of MtsA with the [Fe.sup.2+] ion bound to the side chains of His68, His140, Glu206, and Asp281, at a totally enclosed site between the two domains of the protein. The mutational analysis of the binding site provide insight into the critical role of His140 towards fully functional binding site and other secondary binding sites that might explain the binding behavior of MtsA for metal ions other than [Fe.sup.2+].

The structural characterization of six new depsipeptides belonging to two different structural classes, celebesides A-C and theopapuamides B-D, isolated from the marine sponge Siliquariaspongia mirabilis is described. Theopapuamide A-C has exhibited strong antifungal activity toward amphotericin B-resistant Candida albicans and its parent strain, whereas celebesides has displayed anti-HIV activity due to presence of phosphoserine.