Kinetic Parameters for tmRNA Binding to Alanyl-tRNA Synthetase and Elongation Factor Tu from Escherichia coli

Aminoacylation and transportation of tmRNA to stalled ribosomes constitute prerequisite steps for trans-translation, a process facilitating the release of stalled ribosomes from 3‘ ends of truncated mRNAs and the degradation of incompletely synthesized proteins. Kinetic analysis of the aminoacylatio...

Full description

Saved in:
Bibliographic Details
Published in:Biochemistry (Easton) 2000-03, Vol.39 (10), p.2652-2658
Main Authors: Barends, Sharief, Wower, Jacek, Kraal, Barend
Format: Article
Language:English
Subjects:
Acylation
Alanine-tRNA Ligase - genetics
Alanine-tRNA Ligase - metabolism
Biopolymers - metabolism
Escherichia coli - enzymology
Escherichia coli - genetics
Escherichia coli - metabolism
Kinetics
Peptide Elongation Factor Tu - genetics
Peptide Elongation Factor Tu - metabolism
RNA, Messenger - metabolism
RNA, Transfer, Ala - genetics
RNA, Transfer, Ala - metabolism
Thermodynamics
Transcription, Genetic
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Aminoacylation and transportation of tmRNA to stalled ribosomes constitute prerequisite steps for trans-translation, a process facilitating the release of stalled ribosomes from 3‘ ends of truncated mRNAs and the degradation of incompletely synthesized proteins. Kinetic analysis of the aminoacylation of tmRNA indicates that tmRNA has both a lower affinity and a lower turnover number than cognate tRNAAla for alanyl-tRNA synthetase, resulting in a 75-fold lower k cat/K M value. The association rate constant of Ala-tmRNA for elongation factor Tu in complex with GTP is about 150-fold lower than that of Ala-tRNAAla, whereas its dissocation rate constant is about 5-fold lower. These observations can be interpreted to suggest that additional factors facilitate tmRNA binding to ribosomes.
ISSN:0006-2960
1520-4995
DOI:10.1021/bi992439d