Conservation and variation between Rhodobacter capsulatus and Escherichia coli Tat systems

verfasst von
Ute Lindenstrauß, Thomas Brüser
Abstract

The Tat system allows the translocation of folded and often cofactor-containing proteins across biological membranes. Here, we show by an interspecies transfer of a complete Tat translocon that Tat systems are largely, but not fully, interchangeable even between different classes of proteobacteria. The Tat apparatus from the α-proteobacterium Rhodobacter capsulatus was transferred to a Tat-deficient Escherichia coli strain, which is a γ-proteobacterium. Similar to that of E. coli, the R. capsulatus Tat system consists of three components, rc-TatA, rc-TatB, and rc-TatC. A fourth gene (rc-tatF) is present in the rc-tatABCF operon which has no apparent relevance for translocation. The translational starts of rc-tatC and rc-tatF overlap in four nucleotides (ATGA) with the preceding tat genes, pointing to efficient translational coupling of rc-tatB, rc-tatC, and rc-tatF. We show by a variety of physiological and biochemical assays that the R. capsulatus Tat system functionally targets the E. coli Tat substrates TorA, AmiA, AmiC, and formate dehydrogenase. Even a Tat substrate from a third organism is accepted, demonstrating that usually Tat systems and Tat substrates from different proteobacteria are compatible with each other. Only one exceptional Tat substrate of E. coli, a membrane-anchored dimethyl sulfoxide (DMSO) reductase, was not targeted by the R. capsulatus Tat system, resulting in a DMSO respiration deficiency. Although the general features of Tat substrates and translocons are similar between species, the data indicate that details in the targeting pathways can vary considerably.

Organisationseinheit(en)
Institut für Mikrobiologie
Externe Organisation(en)
Martin-Luther-Universität Halle-Wittenberg
Typ
Artikel
Journal
Journal of Bacteriology
Band
188
Seiten
7807-7814
Anzahl der Seiten
8
ISSN
0021-9193
Publikationsdatum
11.2006
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Mikrobiologie, Molekularbiologie
Elektronische Version(en)
https://doi.org/10.1128/JB.01139-06 (Zugang: Offen)