1a5q
P93A VARIANT OF BOVINE PANCREATIC RIBONUCLEASE A
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OverviewOverview
The Tyr92-Pro93 peptide group of bovine pancreatic ribonuclease A (RNase, A) exists in the cis conformation in the native state. From, unfolding/refolding kinetic studies of the disulfide-intact wild-type, protein and of a variant in which Pro93 had been replaced by Ala, it had, been suggested that the Tyr92-Ala93 peptide group also exists in the cis, conformation in the native state. Here, we report the crystal structure of, the P93A variant. Although there is disorder in the region of residues 92, and 93, the best structural model contains a cis peptide at this position, lending support to the results of the kinetics experiments. We also report, the crystal structure of the C[40, 95]A variant, which is an analog of the, major rate-determining three-disulfide intermediate in the oxidative, folding of RNase A, missing the 40-95 disulfide bond. As had been detected, by NMR spectroscopy, the crystal structure of this analog shows disorder, in the region surrounding the missing disulfide. However, the global chain, fold of the remainder of the protein, including the disulfide bond between, Cys65 and Cys72, appears to be unaffected by the mutation.
About this StructureAbout this Structure
1A5Q is a Single protein structure of sequence from Bos taurus with SO4 as ligand. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of two mutants that have implications for the folding of bovine pancreatic ribonuclease A., Pearson MA, Karplus PA, Dodge RW, Laity JH, Scheraga HA, Protein Sci. 1998 May;7(5):1255-8. PMID:9605332
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