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Shlyapnikov S. V. Lunin V. V. Blagova E. V. Abaturov L. V. Perbandt M. Betzel Ch. Mikhailov A. M. 《Russian Journal of Bioorganic Chemistry》2002,28(1):20-27
Structural and functional characteristics were compared for wild-type nuclease from Serratia marcescens, which belongs to the family of DNA/RNA nonspecific endonucleases, its mutational forms, and the nuclease I-PpoI from Physarum polycephalum, which is a representative of the Cys-His box-containing subgroup of the superfamily of extremely specific intron-encoded homing DNases. Despite the lack of sequence homology and the overall different topology of the Serratia marcescens and I-PpoI nucleases, their active sites have a remarkable structural similarity. Both of them have a unique magnesium atom in the active site, which is a part of the coordinatively bonded water–magnesium complex involved in their catalytic acts. In the enzyme–substrate complexes, the Mg2+ ion is chelated by an Asp residue, coordinates two oxygen atoms of DNA, and stabilizes the transition state of the phosphate anion and 3"-OH group of the leaving nucleotide. A new mechanism of the phosphodiester bond cleavage, which is common for the Serratia marcescens and I-PpoI nucleases and differs from the known functioning mechanism of the restriction and homing endonucleases, was proposed. It presumes a His residue as a general base for the activation of a non-cluster water molecule at the nucleophilic in line displacement of the 3"-leaving group. A strained metalloenzyme–substrate complex is formed during hydrolysis and relaxes to the initial state after the reaction. 相似文献
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Here we present POCUS (prioritization of candidate genes using statistics), a novel computational approach to prioritize candidate disease genes that is based on over-representation of functional annotation between loci for the same disease. We show that POCUS can provide high (up to 81-fold) enrichment of real disease genes in the candidate-gene shortlists it produces compared with the original large sets of positional candidates. In contrast to existing methods, POCUS can also suggest counterintuitive candidates. 相似文献
6.
Spectrometric studies on stability of tenuazonic acid (TeA) solution in organic solvents 总被引:1,自引:0,他引:1
The stability of tenuazonic acid solution at different temperatures and storage times was studied using methanol, methanol-water
(8:2 v/v), benzene and benzene-acetonitrile (98:2 v/v) as solvents. Solutions were analysed by a spectrometric method TeA
U.V.-spectrum was recorded. Results indicated that the optimum temperature for long-time storage period of tenuazonic acid
solution in any solvent assayed is -20°C. Benzene and benzene-acetonitrile (98:2 v/v) could be advised to make tenuazonic
acid solution which will be stored less than 2 months at 4°C. Methanol and methanolwater (8:2 v/v) are not recommended because
a low stability of TeA solution in this solvents. 相似文献
7.
Andrea Vivian Alvarez-Oxiley Noelita Melo de Sousa Jean-Luc Hornick Kamal Touati Gysbert C van der Weijden Marcel AM Taverne Otto Szenci Jean-François Beckers 《Acta veterinaria Scandinavica》2010,52(1):9
Background
The involvement of placental lactogen (PL) in the regulation of foetal growth has been investigated in different species by in vivo immunomodulation techniques. However, when circulating antibodies are present together with the hormone, the procedure for hormonal measurement becomes considerably complex. The aim of this study was the immunoneutralization of bovine placental lactogen (bPL) concentrations in bovine foetal circulation by direct infusion of rabbit anti-bPL purified immunoglobulins (IgG) via a foetal catheter (in vivo study). The ability of a RIA based on guinea pig anti-bPL antiserum, for the measurement of bPL concentrations in samples containing exogenous rabbit anti-bPL immunoglobulins, was also analyzed in in vitro and in vivo conditions. 相似文献8.
Jan AM van Laar Jasper H Kappen Paul LA van Daele P Martin van Hagen 《Arthritis research & therapy》2009,11(2):109-3
Behçet's disease is a complex vasculitis of unknown etiology. Abundant neutrophils suggest the involvement of innate immunity. Cytokines are skewed to the T-helper-1 pattern. Few sterile organs are easily accessible for analysis in Behçet's disease. Cañete and coworkers identify inflamed joints as a feasible model and suggest the involvement of innate immunity in Behçet's disease. 相似文献
9.
MICHEL ROUX NADIA AMÉZIANE MARC ELEAUME 《Zoological Journal of the Linnean Society》2009,155(1):22-39
The main characters of the stalked crinoids of the family Pentacrinitidae attributed to the genus Teliocrinus are re‐evaluated from a quantitative study of phenotype variation, new observations on arm and stalk articulations, and observation of ontogenetic trends. All of the specimens collected in the northern Indian Ocean belong to the same species, i.e. Teliocrinus springeri (Clark, 1909). However, two phenotypes living at different depths remain valid as subspecies: Teliocrinus springeri springeri (Clark, 1909) and Teliocrinus springeri liliaceus (Clark, 1909). Teliocrinus shares several ontogenetic trends with Endoxocrinus, especially in nonfunctional brachial articulations and stalk symplexies. Its assignment to the Diplocrininae is confirmed. A discussion of its affinities with pentacrinid fossil genera in which the crown is well preserved suggests that Diplocrininae could have first appeared during the Lower Cretaceous. A shortening of brachitaxes and a paedomorphic trend of stalk symplexies are the main other evolutionary traits. Nonfunctional articulations are frequently found at the paedomorphic pole of the heterochronic gradient, without clear derived characters. Classification of pentacrinids mainly based on such symplesiomorphy or paedomorphic characters must be definitively abandoned. However, in post‐Palaeozoic stalked crinoids the scarcity of well‐preserved fossils, the high frequency of paedomorphy, and convergent adaptive characters makes phylogenetic reconstruction only based on morphological characters very difficult and speculative. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155 , 22–39. 相似文献
10.
Olga Nagy Margit Pál Andor Udvardy Christine AM Shirras Imre Boros Alan D Shirras Péter Deák 《Cell division》2012,7(1):1-15