1kh8
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Structure of a cis-proline (P114) to glycine variant of Ribonuclease A
OverviewOverview
Replacement of a cis-proline by glycine at position 114 in ribonuclease A leads to a large decrease in thermal stability and simplifies the refolding kinetics. A crystallographic approach was used to determine whether the decrease in thermal stability results from the presence of a cis glycine peptide bond, or from a localized structural rearrangement caused by the isomerization of the mutated cis 114 peptide bond. The structure was solved at 2.0 A resolution and refined to an R-factor of 19.5% and an R(free) of 21.9%. The overall conformation of the protein was similar to that of wild-type ribonuclease A; however, there was a large localized rearrangement of the mutated loop (residues 110-117-a 9.3 A shift of the Calpha atom of residue 114). The peptide bond before Gly114 is in the trans configuration. Interestingly, a large anomalous difference density was found near residue 114, and was attributed to a bound cesium ion present in the crystallization experiment. The trans isomeric configuration of the peptide bond in the folded state of this mutant is consistent with the refolding kinetics previously reported, and the associated protein conformational change provides an explanation for the decreased thermal stability.
About this StructureAbout this Structure
1KH8 is a Single protein structure of sequence from Bos taurus with and as ligands. Active as Pancreatic ribonuclease, with EC number 3.1.27.5 Full crystallographic information is available from OCA.
ReferenceReference
The crystal structure of the cis-proline to glycine variant (P114G) of ribonuclease A., Schultz DA, Friedman AM, White MA, Fox RO, Protein Sci. 2005 Nov;14(11):2862-70. Epub 2005 Sep 30. PMID:16199662
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