2z9s

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spinqualitylabelsall models 2z9s, resolution 2.9Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Crystal Structure Analysis of rat HBP23/Peroxiredoxin I, Cys52Ser mutant

Overview

Rat HBP23/Prx I belongs to the 2-Cys peroxiredoxin type I family, and, exhibits peroxidase activity coupled with reduced thioredoxin (Trx) as an, electron donor. We analyzed the dimer-oligomer interconversion of, wild-type and mutant HBP23/Prx I by gel filtration, and found that the, Cys52Ser and Cys173Ser mutants existed mostly as decamers, while the wild, type was a mixture of various forms, favoring the decamer at higher, protein concentration, lower ionic salt concentration, and in the presence, of DTT. The Cys83Ser mutant was predominantly dimeric, in agreement with a, previous crystallographic analysis. X-Ray diffraction analysis of the, decameric Cys52Ser mutant revealed a toroidal structure (diameter ~130 A, inside diameter ~55 A, thickness ~45 A). In contrast to human Prx I, which, was recently reported to exist predominantly as the decamer with, Cys83-Cys83 disulfide bonds at all dimer-dimer interfaces, rat HBP23/Prx I, has a Cys83-Cys83 disulfide bond at only one dimer-dimer interface (S-S, separation of ~2.1 A), while the interactions at the other interfaces, (mean S-S separation of 3.6 A) appear to involve hydrophobic and van der, Waals forces. This finding is consistent with gel filtration analyses, showing that the protein readily inter-converts between dimer and, oligomeric forms. The Cys83Ser mutant exhibited similar peroxidase, activity to the wild type, which is exclusively dimeric, in the Trx/Trx, reductase system. At higher concentrations, where the protein was mostly, decameric, less efficient attack of reduced Trx was observed in a 14C-IAA, incorporation experiment. We suggest that the dimer-decamer, interconversion may have a regulatory role.

About this Structure

2Z9S is a Single protein structure of sequence from Rattus norvegicus. Active as Peroxiredoxin, with EC number 1.11.1.15 Full crystallographic information is available from OCA.

Reference

Dimer-oligomer interconversion of wild-type and mutant rat 2-Cys peroxiredoxin: disulfide formation at dimer-dimer interface is not essential for decamerization., Matsumura T, Okamoto K, Iwahara SI, Hori H, Takahashi Y, Nishino T, Abe Y, J Biol Chem. 2007 Nov 1;. PMID:17974571

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