ZIB

Hits per page

hits 1 - 2 | 2 hits

Sorting

Electronic Resource

A novel DnaJ-like protein in Escherichia coli inserts into the cytoplasmic membrane with a Type III topology (1996)

Clarke, David J. ; Jacq, A. ; Holland, I. B.

Oxford, UK : Blackwell Publishing Ltd

Molecular microbiology 20 (1996), S. 0

add to mindlist on the mindlist

Details

ISSN: 1365-2958

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology , Medicine

Notes: We describe a novel Escherichia coli protein, DjlA, containing a highly conserved J-region motif, which is present in the DnaJ protein chaperone family and required for interaction with DnaK. Remarkably, DjlA is shown to be a membrane protein, localized to the inner membrane with the unusual Type III topology (N-out, C-in). Thus, DjlA appears to present an extremely short N-terminus to the periplasm and has a single transmembrane domain (TMD) and a large cytoplasmic domain containing the C-terminal J-region. Analysis of the TMD of DjIA and recently identified homologues in Coxiella burnetti and Haemophilus influenzae revealed a striking pattern of conserved glycines (or rarely alanine), with a four-residue spacing. This motif, predicted to form a spiral groove in the TMD, is more marked than a repeating glycine motif, implicated in the dimerization of TMDs of some eukaryotic proteins. This feature of DjlA could represent a promiscuous docking mechanism for interaction with a variety of membrane proteins. DjlA null mutants can be isolated but these appear rapidly to accumulate suppressors to correct envelope and growth defects. Moderate (10-fold) overproduction of DjlA suppresses a mutation in FtsZ but markedly perturbs cell division and cell-envelope growth in minimal medium. We propose that DjlA plays a role in the correct assembly, activity and/or maintenance of a number of membrane proteins, including two-component signal-transduction systems.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1365-2958.1996.tb02646.x

Permalink

Library	Location	Call Number	Volume/Issue/Year	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

Electronic Resource

Increased sensitivity of E. coli to novobiocin, EDTA and the anticalmodulin drug W7 following overproduction of DjlA requires a functional transmembrane domain (1998)

Bernard, S. ; Clarke, D. J. ; Chen, M. X. ; [et al.]

Springer

Molecular genetics and genomics 259 (1998), S. 645-655

add to mindlist on the mindlist

Details

ISSN: 1617-4623

Keywords: Key wordsE. coli ; DnaJ-like ; DjlA overproduction ; Novobiocin resistance

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract In earlier studies we found that E. coli is sensitive to anticalmodulin drugs such as W7. Mutants that are resistant to this drug were isolated, including wseA1. In an attempt to clone the wseA gene, we isolated a clone that restored sensitivity to the drug in the mutant. We found that this clone in fact suppresses W7 resistance through expression of djlA, which encodes a novel DnaJ-like protein. It was found previously that overproduction of DjlA could induce capsule synthesis via activation of the two-component regulatory pathway RcsC/B. In addition to suppression of wseA1, djlA overexpression increases the sensitivity of cells to EDTA and novobiocin, but not to other drugs tested. Although overexpression of a form of the protein carrying a mutation in, or lacking, the J-region of DjlA also led to increased sensitivity, indicating that the chaperone activity of this protein was not strictly required, the full-length, wild- type protein had a more pronounced effect. In contrast, a point mutation which affects the function of the transmembrane domain but not the localisation or stability of DjlA abolished the effects of DjlA overproduction.