1ay7
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(New page: 200px<br /><applet load="1ay7" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ay7, resolution 1.7Å" /> '''RIBONUCLEASE SA COMPL...)
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Revision as of 09:04, 20 November 2007
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RIBONUCLEASE SA COMPLEX WITH BARSTAR
Overview
We report the 1.7 A resolution structure of RNase Sa complexed with the, polypeptide inhibitor barstar. The crystals are in the hexagonal space, group P65 with unit-cell dimensions a = b = 56.9, c = 135.8 A and the, asymmetric unit contains one molecule of the complex. RNase Sa is an, extracellular microbial ribonuclease produced by Streptomyces, aureofaciens. Barstar is the natural inhibitor of barnase, the, ribonuclease of Bacillus amyloliquefaciens. It inhibits RNase Sa and, barnase in a similar manner by steric blocking of the active site. The, structure of RNase Sa is very similar to that observed in crystals of the, native enzyme and its complexes with nucleotides. Barstar retains the, structure found in its complex with barnase. The accessible surface area, of protein buried in the complex is about 300 A2 smaller and there are, fewer hydrogen bonds in the enzyme-inhibitor interface in RNase Sa-barstar, than in barnase-barstar, providing an explanation of the reduced binding, affinity in the former. Previous studies of barstar complexes have used, mutants of the inhibitor and this is the first structure which includes, wild-type barstar.
About this Structure
1AY7 is a Protein complex structure of sequences from Bacillus amyloliquefaciens and Streptomyces aureofaciens. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
Reference
Recognition of RNase Sa by the inhibitor barstar: structure of the complex at 1.7 A resolution., Sevcik J, Urbanikova L, Dauter Z, Wilson KS, Acta Crystallogr D Biol Crystallogr. 1998 Sep 1;54(Pt 5):954-63. PMID:9757110
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