A stability transition at mildly acidic pH in the alpha-hemolysin (alpha-toxin) from Staphylococcus aureus

被引：14

作者：

Bortoleto, RK

Ward, RJ

机构：

[1] USP, FFCLRP, Dept Chem, Ribeirao Preto, SP, Brazil

[2] UNESP, IBILCE, Dept Phys, Sao Jose Rio Preto, SP, Brazil

来源：

FEBS LETTERS | 1999年 / 459卷 / 03期

基金：

巴西圣保罗研究基金会;

关键词：

alpha-hemolysin; stability transition;

D O I：

10.1016/S0014-5793(99)01246-6

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

The effects of mildly acidic conditions on the free energy of unfolding (Delta G(u)(buff)) of the pore-forming alpha-hemolysin (alpha HL) from Staphylococcus aureus were assessed between pH 5.0 and 7.5 by measuring intrinsic tryptophan fluorescence, circular dichroism and elution time in size exclusion chromatography during urea denaturation, Decreasing the pH from 7.0 to 5.0 reduced the calculated Delta G(u)(buff) from 8.9 to 4.2 kcal moI(-1), which correlates with an increased rate of pore formation previously observed over the same pH range, It is proposed that the lowered surface pH of biological membranes reduces the stability of alpha HL thereby modulating the rate of pore formation. (C) 1999 Federation of European Biochemical Societies.

引用

页码：438 / 442

页数：5

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