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排序方式: 共有9233条查询结果,搜索用时 15 毫秒
941.
942.
Acireductone dioxygenase (ARD) from Klebsiella ATCC 8724 is a metalloenzyme that is capable of catalyzing different reactions with the same substrates (acireductone and O2) depending upon the metal bound in the active site. A model for the solution structure of the paramagnetic Ni2+-containing ARD has been refined using residual dipolar couplings (RDCs) measured in two media. Additional dihedral restraints
based on chemical shift (TALOS) were included in the refinement, and backbone structure in the vicinity of the active site
was modeled from a crystallographic structure of the mouse homolog of ARD. The incorporation of residual dipolar couplings
into the structural refinement alters the relative orientations of several structural features significantly, and improves
local secondary structure determination. Comparisons between the solution structures obtained with and without RDCs are made,
and structural similarities and differences between mouse and bacterial enzymes are described. Finally, the biological significance
of these differences is considered. 相似文献
943.
Chris J. Cotsapas Rohan B.H. Williams Jeremy N. Pulvers David J. Nott Eva K.F. Chan Mark J. Cowley Peter F.R. Little 《Mammalian genome》2006,17(6):490-495
The analysis of the influence of genetic variation on regulation of gene expression at a near-genome-wide level has become
the focus of much recent interest. It is widely appreciated that many genes are expressed in a tissue-specific manner and
that others are more ubiquitously expressed but relatively little is known about how genetic variation might influence these
tissue patterns of gene expression. In this review we discuss what is known about the tissue specificity of the influence
of genetic variation and review the challenges that we face in combining hugely parallel, microarray-based gene analysis with
equally expensive genetic analysis. We conclude that the available data suggest that genetic variation is essentially tissue
specific in its effects upon gene expression and this has important implications for experimental analysis. 相似文献
944.
The purpose of this study was to assess the effect of standardized anterior glenohumeral capsular lesions on axial humeral rotation in a full arc of glenohumeral elevation. Using a testing apparatus, the range of internal and external humeral rotation was assessed in an arc of glenohumeral elevation in the scapular plane with steps of 15 degrees in six isolated shoulder joint specimens. Cutting of the glenohumeral joint capsule 1 cm laterally from, and parallel to the glenoid rim was performed in seven steps of 1 cm till the anterior capsule was cut. Capsular lesions were made in three ways: from inferior, from superior and from the middle of the capsule. Anterior capsular lesions resulted in significant increase of external humeral rotation. This occurred particularly at 15-60 degrees glenohumeral elevation. Lesions of the inferior part of the capsule mainly increased external rotation at 30-60 degrees glenohumeral elevation, lesions of the superior part mainly in lower elevation angles and lesions of the middle more gradually in the range till 60 degrees of glenohumeral elevation. Cutting of the anterior glenohumeral capsule barely increased passive axial humeral rotation at elevation angles over 60 degrees. Above 60 degrees glenohumeral elevation, tightening of the inferior posterior glenohumeral joint capsule prevented both internal and, increasingly, external humeral rotation. From these observations it is concluded that increased external rotation correlates with progressive anterior capsular lesions, mainly below 60 degrees glenohumeral elevation. To assess anterior glenohumeral capsular lesions in patients, axial humeral rotation tests should probably not exceed 60 degrees glenohumeral elevation, i.e. 90 degrees thoracohumeral elevation. 相似文献
945.
Vandebroek T Terwel D Vanhelmont T Gysemans M Van Haesendonck C Engelborghs Y Winderickx J Van Leuven F 《The Journal of biological chemistry》2006,281(35):25388-25397
Phosphorylation of Tau protein and binding to microtubules is complex in neurons and was therefore studied in the less complicated model of humanized yeast. Human Tau was readily phosphorylated at pathological epitopes, but in opposite directions regulated by kinases Mds1 and Pho85, orthologues of glycogen synthase kinase-3beta and cdk5, respectively (1). We isolated recombinant Tau-4R and mutant Tau-P301L from wild type, Delta mds1 and Delta pho85 yeast strains and measured binding to Taxol-stabilized mammalian microtubules in relation to their phosphorylation patterns. Tau-4R isolated from yeast lacking mds1 was less phosphorylated and bound more to microtubules than Tau-4R isolated from wild type yeast. Paradoxically, phosphorylation of Tau-4R isolated from kinase Pho85-deficient yeast was dramatically increased resulting in very poor binding to microtubules. Dephosphorylation promoted binding to microtubules to uniform high levels, excluding other modifications. Isolated hyperphosphorylated, conformationally altered Tau-4R completely failed to bind microtubules. In parallel to Tau-4R, we expressed, isolated, and analyzed mutant Tau-P301L. Total dephosphorylated Tau-4R and Tau-P301L bound to microtubules very similarly. Surprisingly, Tau-P301L isolated from all yeast strains bound to microtubules more extensively than Tau-4R. Atomic force microscopy demonstrated, however, that the high apparent binding of Tau-P301L was due to aggregation on the microtubules, causing their deformation and bundling. Our data explain the pathological presence of granular Tau aggregates in neuronal processes in tauopathies. 相似文献
946.
947.
Identification of a novel human granzyme B inhibitor secreted by cultured sertoli cells 总被引:3,自引:0,他引:3
Sipione S Simmen KC Lord SJ Motyka B Ewen C Shostak I Rayat GR Dufour JM Korbutt GS Rajotte RV Bleackley RC 《Journal of immunology (Baltimore, Md. : 1950)》2006,177(8):5051-5058
Sertoli cells have long since been recognized for their ability to suppress the immune system and protect themselves as well as other cell types from harmful immune reaction. However, the exact mechanism or product produced by Sertoli cells that affords this immunoprotection has never been fully elucidated. We examined the effect of mouse Sertoli cell-conditioned medium on human granzyme B-mediated killing and found that there was an inhibitory effect. We subsequently found that a factor secreted by Sertoli cells inhibited killing through the inhibition of granzyme B enzymatic activity. SDS-PAGE analysis revealed that this factor formed an SDS-insoluble complex with granzyme B. Immunoprecipitation and mass spectroscopic analysis of the complex identified a proteinase inhibitor, serpina3n, as a novel inhibitor of human granzyme B. We cloned serpina3n cDNA, expressed it in Jurkat cells, and confirmed its inhibitory action on granzyme B activity. Our studies have led to the discovery of a new inhibitor of granzyme B and have uncovered a new mechanism used by Sertoli cells for immunoprotection. 相似文献
948.
Jiao K Langworthy M Batts L Brown CB Moses HL Baldwin HS 《Development (Cambridge, England)》2006,133(22):4585-4593
The transforming growth factorbeta (Tgfbeta) signaling pathway plays crucial roles in many biological processes. To understand the role(s) of Tgfbeta signaling during cardiogenesis in vivo and to overcome the early lethality of Tgfbr2(-/-) embryos, we applied a Cre/loxp system to specifically inactivate Tgfbr2 in either the myocardium or the endothelium of mouse embryos. Our results show that Tgfbr2 in the myocardium is dispensable for cardiogenesis in most embryos. Contrary to the prediction from results of previous in vitro collagen gel assays, inactivation of Tgfbr2 in the endocardium does not prevent atrioventricular cushion mesenchyme formation, arguing against its essential role in epithelium-mesenchyme transformation in vivo. We further demonstrate that Tgfbeta signaling is required for the proper remodeling of the atrioventricular canal and for cardiac looping, and that perturbation in Tgfbeta signaling causes the double-inlet left ventricle (DILV) defect. Thus, our study provides a unique mouse genetic model for DILV, further characterization of which suggests a potential cellular mechanism for the defect. 相似文献
949.
950.
GenePro: a Cytoscape plug-in for advanced visualization and analysis of interaction networks 总被引:2,自引:0,他引:2
Vlasblom J Wu S Pu S Superina M Liu G Orsi C Wodak SJ 《Bioinformatics (Oxford, England)》2006,22(17):2178-2179
MOTIVATION: Analyzing the networks of interactions between genes and proteins has become a central theme in systems biology. Versatile software tools for interactively displaying and analyzing these networks are therefore very much in demand. The public-domain open software environment Cytoscape has been developed with the goal of facilitating the design and development of such software tools by the scientific community. RESULTS: We present GenePro, a plugin to Cytoscape featuring a set of versatile tools that greatly facilitates the visualization and analysis of protein networks derived from high-throughput interactions data and the validation of various methods for parsing these networks into meaningful functional modules. AVAILABILITY: The GenePro plugin is available at the website http://genepro.ccb.sickkids.ca. 相似文献