Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.27.3 (RNase T1)
 1,228 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ternary complex formed between RNase T1, guanosine 3',5'-bisphosphate (3',5'-pGp) and Pi crystallizes in the cubic space group I23 with a = 8.706(1) nm. In a previous publication [Lenz, A., Heinemann, U., Maslowska, M. & Saenger, W. (1991) Acta Crystallogr. B47, 521-527], the structure of the complex (in which Pi was not located) was described at a resolution of 0.32 nm. This is now extended to 0.19 nm with newly grown, larger crystals. Refinement with restrained least-squares converged at R = 17.8% for 8027 reflections with [Fo[ > or = 1 sigma ([Fo[); the final model comprises 120 water molecules. 3',5'-pGp is bound to RNase T1 in the anti form, with guanine in the specific recognition site; the 3'-phosphate protrudes into the solvent, and the 5'-phosphate hydrogen bonds with Lys41 O and Asn43 N4. A tetrahedral anion assigned as Pi occupies the catalytic site and hydrogen bonds to the side chains of Tyr38, Glu58, Arg77 and His92. The overall polypeptide fold of RNase T1 in the cubic space group does not differ significantly from that in the orthorhombic space group P2(1)2(1)2(1) except for changes < or = 0.2 nm in loop regions 69-72 and 95-98.
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PMID:Three-dimensional structure of the ternary complex between ribonuclease T1, guanosine 3',5'-bisphosphate and inorganic phosphate at 0.19 nm resolution. 842 41

The crystal structure of a complex of ribonuclease from Streptomyces aureofaciens (RNase Sa) with guanosine-2'-monophosphate (2'-GMP) has been refined against synchrotron data recorded from a single crystal using radiation from beamline X31 at EMBL, Hamburg, and an imaging plate scanner. The crystals are in space group P2(1)2(1)2(1) with cell dimensions a = 64.7, b = 78.8 and c = 39.1 A. The structure has two enzyme molecules in the asymmetric unit, complexed with 2'-GMP inhibitor with occupancies of 1 and 2/3 (different to the 3'-GMP complex crystal structure where only one of the two independent RNase Sa molecules binds nucleotide), 492 associated water molecules and one sulfate ion, and was refined using all data between 10.0 and 1.7 A to a final crystallographic R factor of 13.25%. Binding of the base to the enzyme confirms the basis for the guanine specificity but the structural results still do not provide direct evidence of the identity and role of the particular residues involved in the catalytic process. New native RNase Sa data to 1.8 A were recorded to provide a reference set measured under comparable experimental conditions. The crystals are in the same space group and have the same lattice as those of the 2'-GMP complex. The native structure with 423 water molecules was refined in a similar manner to the complex to a final R factor of 13.87%. 1.77 A resolution data were independently measured on a 2'-GMP complex crystal at UCLA using an R-AXIS II image plate scanner mounted on a conventional source. The cell dimensions were essentially the same as above. 2'-GMP was bound more fully to molecule A than to molecule B of the RNase Sa. The structure was refined to an R factor of 14.64% with 388 water molecules. This work follows on from the structure determination of native RNase Sa and its complex with 3'-GMP [Sevcik, Dodson & Dodson (1991). Acta Cryst. B47, 240-253].
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PMID:Complex of ribonuclease from Streptomyces aureofaciens with 2'-GMP at 1.7 A resolution. 1529 31