3rsp
From Proteopedia
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STRUCTURE OF THE P93G VARIANT OF RIBONUCLEASE A
Overview
The peptide bonds preceding Pro 93 and Pro 114 of bovine pancreatic, ribonuclease A (RNase A) are in the cis conformation. The trans-to-cis, isomerization of these bonds had been indicted as the slow step during, protein folding. Here, site-directed mutagenesis was used to replace Pro, 93 or Pro 114 with a glycine residue, and the crystalline structure of the, P93G variant was determined by X-ray diffraction analysis to a resolution, of 1.7 A. This structure is essentially identical to that of the wild-type, protein, except for the 91-94 beta-turn containing the substitution. In, the wild-type protein, the beta-turn is of type VIa. In the P93G variant, this turn is of type II with the peptide bond preceding Gly 93 being, trans. The thermal stabilities of the P93G and P114G variants were, assessed by differential scanning calorimetry and thermal denaturation, experiments monitored by ultraviolet spectroscopy. The value of delta, deltaGm which reports on the stability lost in the variants, is 1.5-fold, greater for the P114G variant than for the P93G variant. The greater, stability of the P93G variant is likely due to the relatively facile, accommodation of residues 91-94 in a type II turn, which has a preference, for a glycine residue in its i + 2 position.
About this Structure
3RSP is a Single protein structure of sequence from Bos taurus with CL as ligand. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Structure known Active Sites: B1, B2, P1 and P2. Full crystallographic information is available from OCA.
Reference
Structure and stability of the P93G variant of ribonuclease A., Schultz LW, Hargraves SR, Klink TA, Raines RT, Protein Sci. 1998 Jul;7(7):1620-5. PMID:9684895
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