1rsn
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(New page: 200px<br /><applet load="1rsn" size="450" color="white" frame="true" align="right" spinBox="true" caption="1rsn, resolution 2.0Å" /> '''RIBONUCLEASE (RNASE S...)
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Revision as of 23:43, 20 November 2007
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RIBONUCLEASE (RNASE SA) (E.C.3.1.4.8) COMPLEXED WITH EXO-2',3'-CYCLOPHOSPHOROTHIOATE
Overview
The structure of the complex of ribonuclease from Streptomyces, aureofaciens (RNase Sa) with exo guanosine 2',3'-cyclophosphorothioate has, been refined against 0.2-nm resolution synchrotron data using, as a, starting model, coordinates from the RNase Sa: 2'-GMP complex. The, refinement was based on all data over 1.0-0.2 nm and converged to a, crystallographic R factor of 11.9%. This is the first structure of a, microbial ribonuclease complexed with a 2',3'-cyclophosphorothioate, which, is a thio analogue of the intermediate of the two-step reaction. However, exo guanosine 2',3'-cyclophosphorothioate is bound in a non-functional, mode and is not hydrolysed. This structure therefore does not provide, direct evidence on the identity of the amino acid residues responsible for, catalytic cleavage of the substrate. However, based on present and, previous results, a plausible model is proposed for the complex of the, cyclic intermediate which acts as substrate for the second step of the, catalysis.
About this Structure
1RSN is a Single protein structure of sequence from Streptomyces aureofaciens with SO4 and SGP as ligands. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
Reference
Complex of ribonuclease Sa with a cyclic nucleotide and a proposed model for the reaction intermediate., Sevcik J, Zegers I, Wyns L, Dauter Z, Wilson KS, Eur J Biochem. 1993 Aug 15;216(1):301-5. PMID:8396032
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