کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2189980 1096230 2006 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Factors Dictating the Pseudocatalytic Efficiency of Avidins
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی بیولوژی سلول
پیش نمایش صفحه اول مقاله
Factors Dictating the Pseudocatalytic Efficiency of Avidins
چکیده انگلیسی

The hydrolysis of biotinyl p-nitrophenyl ester (BNP) by a series of avidin derivatives was examined. Surprisingly, a hyperthermostable avidin-related protein (AVR4) was shown to display extraordinary yet puzzling hydrolytic activity. In order to evaluate the molecular determinants that contribute to the reaction, the crystal structure of AVR4 was compared with those of avidin, streptavidin and key mutants of the two proteins in complex with biotinyl p-nitroanilide (BNA), the inert amide analogue of BNP. The structures revealed that a critical lysine residue contributes to the hydrolysis of BNP by avidin but has only a minor contribution to the AVR4-mediated reaction. Indeed, the respective rates of hydrolysis among the different avidins reflect several molecular parameters, including binding-site architecture, the availability of the ligand to solvent and the conformation of the ligand and consequent susceptibility to efficient nucleophilic attack. In avidin, the interaction of BNP with Lys111 and disorder of the L3,4 loop (and consequent solvent availability) together comprise the major driving force behind the hydrolysis, whereas in AVR4 the status of the ligand (the pseudo-substrate) is a major distinguishing feature. In the

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Biology - Volume 358, Issue 3, 5 May 2006, Pages 754–763
نویسندگان
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