The role of a topologically conserved isoleucine in glutathione transferase structure, stability and function

被引：6

作者：

Achilonu, Ikechukwu ^{[1
]}

Gildenhuys, Samantha ^{[1
]}

Fisher, Loren ^{[1
]}

Burke, Jonathan ^{[1
]}

Fanucchi, Sylvia ^{[1
]}

Sewell, B. Trevor ^{[2
]}

Fernandes, Manuel ^{[3
]}

Dirr, Heini W. ^{[1
]}

机构：

[1] Univ Witwatersrand, Sch Mol & Cell Biol, Prot Struct Funct Res Unit, ZA-2050 Johannesburg, South Africa

[2] Univ Cape Town, Electron Microscope Unit, ZA-7701 Rondebosch, South Africa

[3] Univ Witwatersrand, Sch Chem, ZA-2050 Johannesburg, South Africa

来源：

ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS | 2010年 / 66卷

基金：

新加坡国家研究基金会;

关键词：

FOLDING MECHANISM; PROTEIN; EVOLUTION; LIGANDIN; SUBUNIT;

D O I：

10.1107/S1744309110019135

中图分类号：

Q5 [生物化学];

学科分类号：

071010 ; 081704 ;

摘要：

The common fold shared by members of the glutathione-transferase (GST) family has a topologically conserved isoleucine residue at the N-terminus of helix 3 which is involved in the packing of helix 3 against two beta-strands in domain 1. The role of the isoleucine residue in the structure, function and stability of GST was investigated by replacing the Ile71 residue in human GSTA1-1 by alanine or valine. The X-ray structures of the I71A and I71V mutants resolved at 1.75 and 2.51 angstrom, respectively, revealed that the mutations do not alter the overall structure of the protein compared with the wild type. Urea-induced equilibrium unfolding studies using circular dichroism and tryptophan fluorescence suggest that the mutation of Ile71 to alanine or valine reduces the stability of the protein. A functional assay with 1-chloro-2,4-dinitrobenzene shows that the mutation does not significantly alter the function of the protein relative to the wild type. Overall, the results suggest that conservation of the topologically conserved Ile71 maintains the structural stability of the protein but does not play a significant role in catalysis and substrate binding.

引用

页码：776 / 780

页数：5

共 36 条

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