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 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.
Related Citations:
Complex of Ribonuclease from Streptomyces Aureofaciens with 2'-Gmp at 1.7 Angstroms Resolution Sevcik, J., Hill, C.P., Dauter, Z., Wilson, K.S. (1993) Acta Crystallogr D Biol Crystallogr 49: 257
Determination and Restrained Least-Squares Refinement of the Structure of Ribonuclease And its Complex with 3'-Guanylic Acid at 1.8 Angstroms Resolution Sevcik, J., Dodson, E.J., Dodson, G.G. (1991) Acta Crystallogr B 47: 240
Comparison of Active Sites of Some Microbial Ribonucleases: Structural Basis for Guanylic Specificity Sevcik, J., Sanishvili, R.G., Pavlovsky, A.G., Polyakov, K.M. (1990) Trends Biochem Sci 5: 158
Amino Acid Sequence Determination of Guanyl-Specific Ribonuclease Sa from Streptomyces Aureofaciens Shlyapnikov, S.U., Both, V., Kulikov, V.A., Dementiev, A.A., Sevcik, J., Zelinka, J. (1986) FEBS Lett 209: 335
Exocellular Ribonuclease from Streptomyces Aureofaciens. I. Isolation and Purification Bacova, M., Zelinkova, E., Zelinka, J. (1971) Biochim Biophys Acta 235: 335
Exocellular Ribonuclease from Streptomyces Aureofaciens. II. Properties and Specificity Bacova, M., Zelinkova, E., Zelinka, J. (1971) Biochim Biophys Acta 235: 343
Organizational Affiliation:
Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava.
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