Quality, Quantity and Type of Child Care : Effects on Child Development in the USA

ABC transport systems account for most import of necessary nutrients in bacteria. The periplasmic binding component (or an equivalent membrane-anchored protein) is critical to recognizing the cognate ligand and directing it to the appropriate membrane permease. Here we report X-ray structures of D-xylose-binding protein from Escherichia coli in ligand-free open, ligand-bound open and ligand-bound closed forms, at 2.15, 2.2, and 2.2-Å resolution, respectively. The ligand-bound open form is the first such structure to be reported at high resolution; the combination of the three different forms from the same protein furthermore gives unprecedented detail concerning the conformational changes involved in binding protein function. As is typical for the structural family, the protein has two similar globular domains, which are connected by a three-stranded hinge region. The open liganded structure shows that xylose binds first to the C-terminal domain, with only very small conformational changes resulting. After a 34° closing motion, additional interactions are formed with the N-terminal domain; changes in this domain are larger, and serve to make the structure more ordered near the ligand. An analysis of the interactions suggests why xylose is the preferred ligand. Further, a comparison with the most closely related proteins in the structural family shows that the conformational changes are distinct in each type of binding protein, which may have implications for how the individual proteins act in concert with their respective membrane permeases

Structures of two fimbrial adhesins, AtfE and UcaD, from the uropathogen Proteus mirabilis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146321/1/ayd2jb5004.pd

CYPome of the conifer pathogen Heterobasidion irregulare : Inventory, phylogeny, and transcriptional analysis of the response to biocontrol

The molecular mechanisms underlying the interaction of the pathogen, Heterobasidion annosum s.l., the conifer tree and the biocontrol fungus, Phlebiopsis gigantea have not been fully elucidated. Members of the cytochrome P450 (CYP) protein family may contribute to the detoxification of components of chemical defence of conifer trees by H. annosum during infection. Additionally, they may also be involved in the interaction between H. annosum and P. gigantea. A genome-wide analysis of CYPs in Heterobasidion irregulare was carried out alongside gene expression studies. According to the Standardized CYP Nomenclature criteria, the H. irregulare genome has 121 CYP genes and 17 CYP pseudogenes classified into 11 clans, 35 families, and 64 subfamilies. Tandem CYP arrays originating from gene duplications and belonging to the same family and subfamily were found. Phylogenetic analysis showed that all the families of H. irregulare CYPs were monophyletic groups except for the family CYP5144. Microarray analysis revealed the transcriptional pattern for 130 transcripts of CYP-encoding genes during growth on culture filtrate produced by P. gigantea. The high level of P450 gene diversity identified in this study could result from extensive gene duplications presumably caused by the high metabolic demands of H. irregulare in its ecological niches. (C) 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.Peer reviewe

Особливості трудового виховання і профорієнтації в умовах нової парадигми освіти

(uk) У статті розкривається проблема формування майбутнього учителя-предметника, готового до забезпечення трудового виховання у професійній діяльності у світлі нової освітньої парадигми

N-glycans of Human Protein C Inhibitor: Tissue-Specific Expression and Function

Protein C inhibitor (PCI) is a serpin type of serine protease inhibitor that is found in many tissues and fluids in human, including blood plasma, seminal plasma and urine. This inhibitor displays an unusually broad protease specificity compared with other serpins. Previous studies have shown that the N-glycan(s) and the NH2-terminus affect some blood-related functions of PCI. In this study, we have for the first time determined the N-glycan profile of seminal plasma PCI, by mass spectrometry. The N-glycan structures differed markedly compared with those of both blood-derived and urinary PCI, providing evidence that the N-glycans of PCI are expressed in a tissue-specific manner. The most abundant structure (m/z 2592.9) had a composition of Fuc3Hex5HexNAc4, consistent with a core fucosylated bi-antennary glycan with terminal Lewisx. A major serine protease in semen, prostate specific antigen (PSA), was used to evaluate the effects of N-glycans and the NH2-terminus on a PCI function related to the reproductive tract. Second-order rate constants for PSA inhibition by PCI were 4.3±0.2 and 4.1±0.5 M−1s−1 for the natural full-length PCI and a form lacking six amino acids at the NH2-terminus, respectively, whereas these constants were 4.8±0.1 and 29±7 M−1s−1 for the corresponding PNGase F-treated forms. The 7–8-fold higher rate constants obtained when both the N-glycans and the NH2-terminus had been removed suggest that these structures jointly affect the rate of PSA inhibition, presumably by together hindering conformational changes of PCI required to bind to the catalytic pocket of PSA

Structural studies of cellulose and chitin active enzymes

Cellulose and chitin, the main ways of storing biological energy in nature, also play a vital role in the structures of many organisms. Cellulose is the main structural component in plants whereas chitin is found in invertebrates and fungi. Gaining a better understanding of the degradation of these polymers can have direct or indirect economic impact. This thesis summarizes the structural perspectives of the cellulose and chitin degradation machinery. The white-rot fungus Phanerochaete chrysosporium has six cellobiohydrolases, which are expressed differentially with varying stimuli and time intervals. X-ray crystal structures of one of the six isozymes (Pc_Cel7D) suggested that it uses a retention mechanism and acts from the reducing end of cellulose chain. Homology modeling of the other enzymes supported the same sort of mechanism for all except one (Pc_Cel7B) and considerably different dynamic properties for two isozymes (Pc_Cel7A and Pc_Cel7B). Piromyces sp. strain E2 Cel9A and Cel6A as well as Piromyces equi Cel6A are modular structures, which function as parts of the fungal cellulosome of the respective organisms. Homology modeling supported the conclusion that Cel9A is an endoglucanase having a wide active site cleft and a conserved calcium-binding site with an inverting catalytic mechanism, whereas the Cel6As are processive cellobiohydrolases that act via an inverting mechanism that releases cellobiose from the non-reducing end of the cellulose chain. Brassica juncea endo acting chitinase is a pathogenesis-related protein that acts in defense of the plant. A homology model of the catalytic module was useful in designing mutants that helped us to understand the substrate binding and catalytic processes. X-ray crystal structures of the catalytic module and a mutant extended the knowledge of how the enzyme acts during the catalysis, with conformational changes opening and closing the enzyme. The homology model of yam, Dioscorea opposita, class IV endochitinase suggests that this enzyme catalyzes chitin cleavage via an inverting mechanism. Deletions in class IV chitinases compared to class I/II cluster at the ends of the substrate-binding cleft, shortening it by one glycosyl unit at each end. The shorter cleft might be expected to recognize and grasp a small section of exposed chitin on a fungal hyphal wall, more effectively attacking it

Structure and function of chitinases from glycoside hydrolase family 19

Glycoside hydrolase family 19 chitinases are found in plants, bacteria and viruses, playing various roles. Plant chitinases are important for defence and development, whereas bacterial examples are useful for nutrition. The available structural studies show that family 19 enzymes are highly alpha-helical bi-lobed structures with a wide cleft lined by conserved residues important for catalysis and substrate binding. Class I and II plant chitinases possess loops which are absent in class IV and/or bacterial chitinases. One of the loops seems to retain a significant function. These inverting endochitinases demonstrate a possible opening-closing mechanism of the catalytic cleft during chitin hydrolysis due to loop movements. However, complex structures with inhibitors and/or substrate/product analogues are required for a deeper understanding of these enzymes. (C) 2011 Society of Chemical Industr