PMID:10369667

Citation	Duong, F and Wickner, W (1999) The PrlA and PrlG phenotypes are caused by a loosened association among the translocase SecYEG subunits. EMBO J. 18:3263-70
Abstract	prlA mutations in the gene encoding the SecY subunit of the membrane domain of the Escherichia coli preprotein translocase confer many phenotypes: enhanced translocation rates, increased affinity for SecA, diminished requirement for functional leader sequences, reduced proton-motive force (PMF) dependence of preprotein translocation and facilitated translocation of preproteins with folded domains. We now report that both prlA and prlG mutations weaken the associations between the SecY, SecE and SecG subunits of the translocase. This loosened association increases the initiation of translocation by facilitating the insertion of SecA with its bound preprotein but reduces the stimulatory effect of the PMF during the initial step of translocation. Furthermore, the originally isolated prlA4 mutant, which possesses a particularly labile SecYEG complex, acquired a secondary mutation that restored the stability while conserving the flexibility of the complex. Combinations of certain prlA and prlG mutations, known to cause synthetic lethality in vivo, dramatically loosen subunit association and lead to complete disassembly of SecYEG. These findings underscore the importance of the loosened SecYEG association for the Prl phenotypes. We propose a model in which each of the PrlA and PrlG phenotypes derive from this enhanced SecYEG conformational flexibility.
Links	PubMed PMC1171407 Online version:10.1093/emboj/18.12.3263
Keywords	Adenosine Triphosphatases/chemistry; Adenosine Triphosphatases/metabolism; Alleles; Bacterial Proteins/chemistry; Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Biological Transport; Escherichia coli/genetics; Escherichia coli/metabolism; Escherichia coli Proteins; Genes, Suppressor/genetics; Membrane Proteins/metabolism; Membrane Transport Proteins; Models, Biological; Mutation; Phenotype; Protein Binding; Protein Conformation; Protein Precursors/chemistry; Protein Precursors/metabolism; Proton-Motive Force/physiology; Suppression, Genetic
edit table

Significance

You can help EcoliWiki by summarizing why this paper is useful

Useful Materials and Methods

You can help Ecoliwiki by describing the useful materials (strains, plasmids, antibodies, etc) described in this paper.

Annotations

<annotationlinks/>

EcoliWiki Links

Add links to pages that link here (e.g. gene, product, method pages)

References

See Help:References for how to manage references in EcoliWiki.