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Modification of PATase by L/F-transferase generates a ClpS-dependent N-end rule substrate in Escherichia coli.

Authors :
Ninnis RL
Spall SK
Talbo GH
Truscott KN
Dougan DA
Source :
The EMBO journal [EMBO J] 2009 Jun 17; Vol. 28 (12), pp. 1732-44. Date of Electronic Publication: 2009 May 14.
Publication Year :
2009

Abstract

The N-end rule pathway is conserved from bacteria to man and determines the half-life of a protein based on its N-terminal amino acid. In Escherichia coli, model substrates bearing an N-degron are recognised by ClpS and degraded by ClpAP in an ATP-dependent manner. Here, we report the isolation of 23 ClpS-interacting proteins from E. coli. Our data show that at least one of these interacting proteins--putrescine aminotransferase (PATase)--is post-translationally modified to generate a primary N-degron. Remarkably, the N-terminal modification of PATase is generated by a new specificity of leucyl/phenylalanyl-tRNA-protein transferase (LFTR), in which various combinations of primary destabilising residues (Leu and Phe) are attached to the N-terminal Met. This modification (of PATase), by LFTR, is essential not only for its recognition by ClpS, but also determines the stability of the protein in vivo. Thus, the N-end rule pathway, through the ClpAPS-mediated turnover of PATase may have an important function in putrescine homeostasis. In addition, we have identified a new element within the N-degron, which is required for substrate delivery to ClpA.

Details

Language :
English
ISSN :
1460-2075
Volume :
28
Issue :
12
Database :
MEDLINE
Journal :
The EMBO journal
Publication Type :
Academic Journal
Accession number :
19440203
Full Text :
https://doi.org/10.1038/emboj.2009.134