EFFECT OF INORGANIC PYROPHOSPHATE ON THE PRETRANSFER PROOFREADING IN THE ISOLEUCYL-TRANSFER RNA-SYNTHETASE FROM ESCHERICHIA-COLI

被引：6

作者：

AIRAS, RK

机构：

[1] Department of Biochemistry, University of Turku, Turku

来源：

EUROPEAN JOURNAL OF BIOCHEMISTRY | 1992年 / 210卷 / 02期

关键词：

D O I：

10.1111/j.1432-1033.1992.tb17441.x

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：

A total rate equation was used to calculate the discrimination of valine by the isoleucyl-tRNA synthetase from Escherichia coli. The PP(i) present in the cell makes the backward reaction or the pyrophosphorolysis of the E . aa-AMP possible. If the E . Ile-Amp has been corrected for wrong aminoacyl adenylation by the pretransfer proofreading, the pyrophosphorolysis rapidly equilibrates the corrected E . Ile-AMP with E . Ile and thus spoils the effect of the proofreading. The loss of the corrected species is avoided if there is a barrier (perhaps conformational) formed by a slow reaction step between the noncorrected E . Ile-AMP and the corrected *E(tRNA)Ile-AMP. If such a slow conformational change exists, the increase in accuracy from the pretransfer proofreading would be benefitial, and, in addition, the PP(i) increases the accuracy by optimizing the initial discrimination of the wrong amino acid.

引用

页码：451 / 454

页数：4

共 19 条

[1] ON THE NON-LINEAR EADIE PLOTS OF THE TRANSFER-RNA KINETICS AND NON-LINEAR DIXON PLOTS OF THE PPI INHIBITION-KINETICS OF THE AMINOACYL-TRANSFER RNA-SYNTHETASES - AN ANALYSIS OF THE AMINOACYLATION OF TRANSFER-RNA IN A MODEL REACTIO [J].