3rsp: Difference between revisions
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==Overview== | ==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, ... | 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== | ==About this Structure== | ||
3RSP is a | 3RSP is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bos_taurus Bos taurus] with CL as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Pancreatic_ribonuclease Pancreatic ribonuclease], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.27.5 3.1.27.5] Structure known Active Sites: B1, B2, P1 and P2. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=3RSP OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: x-ray diffraction]] | [[Category: x-ray diffraction]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 14:56:50 2007'' | ||
