盐酸胍变性过程中泛硫乙胺水解酶活性位点的构象变化。

Conformational changes at the active site of pantetheine hydrolase during denaturation by guanidine hydrochloride.

作者信息

Pitari G, D'Archivio A A, Di Leandro L, Antonini G, Panatta A, Tettamanti E, Duprè S, Malatesta F

机构信息

Dipartimento di Biologia di Base e Applicata, University of L'Aquila, Italy.

出版信息

J Protein Chem. 1999 Oct;18(7):785-9. doi: 10.1023/a:1020685619173.

DOI:10.1023/a:1020685619173

PMID:10691189

Abstract

Conformational changes at the active site of pantetheine hydrolase (EC3.5.1.-) during guanidine hydrochloride (GndHCl) denaturation were investigated by UV and circular dichroism spectroscopy and by electron spin resonance spectroscopy, following the spectral behaviour of the nitroxide radicals (N-(1-oxyl-2,2,5,5,-tetramethyl-3-pyrrolidinyl) iodacetamide) covalently linked to the two active site cysteine residues. At low denaturant concentrations (0.2 M) no conformational changes may be observed, whereas the catalytic activity, is strongly affected. The results indicate that the active site of pantetheine hydrolase is labile and unfolds under conditions in which no global tertiary structure modifications can be observed.

摘要

通过紫外光谱、圆二色光谱以及电子自旋共振光谱，研究了盐酸胍（GndHCl）变性过程中泛硫乙胺水解酶（EC3.5.1.-）活性位点的构象变化，跟踪与两个活性位点半胱氨酸残基共价连接的氮氧自由基（N-(1-氧基-2,2,5,5-四甲基-3-吡咯烷基)碘乙酰胺）的光谱行为。在低变性剂浓度（0.2 M）下，未观察到构象变化，而催化活性受到强烈影响。结果表明，泛硫乙胺水解酶的活性位点不稳定，在未观察到整体三级结构修饰的条件下会发生解折叠。