3rnt
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CRYSTAL STRUCTURE OF GUANOSINE-FREE RIBONUCLEASE T1, COMPLEXED WITH VANADATE(V), SUGGESTS CONFORMATIONAL CHANGE UPON SUBSTRATE BINDING
OverviewOverview
Ribonuclease T1 was crystallized in the presence of vanadate(V). The, crystal structure was solved by molecular replacement and refined by, least-squares methods using stereochemical restraints. The refinement was, based on data between 10 and 1.8 A and converged at a crystallographic R, factor of 0.137. Except for the substrate-recognition site the, three-dimensional structure of ribonuclease T1 closely resembles the, structure of the enzyme complexed with guanosine 2'-phosphate and its, derivatives. A tetrahedral anion was found at the catalytic site and, identified as H2VO4-. This is the first crystal structure of ribonuclease, T1 determined in the absence of bound substrate analogue. Distinct, structural differences between guanosine-free and complexed ribonuclease, T1 are observed at the base-recognition site: The side chains of Tyr45 and, Glu46 and the region around Asn98 changed their conformations, and the, peptide bond between Asn43 and Asn44 has turned around by 140 degrees. We, suggest that the structural differences seen in the crystal structures of, free and complexed ribonuclease T1 are related to conformational, adjustments associated with the substrate binding process.
About this StructureAbout this Structure
3RNT is a Single protein structure of sequence from Aspergillus oryzae with CA and VO4 as ligands. Active as Ribonuclease T(1), with EC number 3.1.27.3 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of guanosine-free ribonuclease T1, complexed with vanadate (V), suggests conformational change upon substrate binding., Kostrewa D, Choe HW, Heinemann U, Saenger W, Biochemistry. 1989 Sep 19;28(19):7592-600. PMID:2514790
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