1AY7

RIBONUCLEASE SA COMPLEX WITH BARSTAR

Summary for 1AY7

• Entry DOI: 10.2210/pdb1ay7/pdb
• Descriptor: GUANYL-SPECIFIC RIBONUCLEASE SA, BARSTAR (3 entities in total)
• Functional Keywords: ribonuclease, inhibitor, streptomyces aureofaciens, complex (enzyme-inhibitor), complex (enzyme-inhibitor) complex, complex (enzyme/inhibitor)
• Biological source: Streptomyces aureofaciens; More
• Cellular location: Secreted: P05798; Cytoplasm: P11540
• Total number of polymer chains: 2
• Total formula weight: 20804.03

Authors

Sevcik, J.,Urbanikova, L.,Dauter, Z.,Wilson, K.S. (deposition date: 1997-11-14, release date: 1999-03-02, Last modification date: 2024-10-16)

Primary citation

Sevcik, J.,Urbanikova, L.,Dauter, Z.,Wilson, K.S.
Recognition of RNase Sa by the inhibitor barstar: structure of the complex at 1.7 A resolution.
Acta Crystallogr.,Sect.D, 54:954-963, 1998

PubMed Abstract: 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.

PubMed: 9757110
DOI: 10.1107/S0907444998004429

Experimental method

X-RAY DIFFRACTION (1.7 Å)