Characterisation and membrane assembly of the TatA component of the Escherichia coli twin-arginine protein transport system

Ida Procelli, Erik de Leeuw, Russell Wallis, Els van den Brink-van der Laan, Ben de Kruijff, B.A. Wallace, Tracy Palmer, Ben C. Berks

Research output: Contribution to journalArticlepeer-review

89 Citations (Scopus)

Abstract

Proteins bearing a signal peptide with a consensus twin-arginine motif are translocated via the Tat pathway, a multiprotein system consisting minimally of the integral inner membrane proteins TatA, TatB, and TatC. On a molar basis, TatA is the major pathway component. Here we show that TatA can be purified independently of the other Tat proteins as a 460 kDa homooligomeric complex. Homooligomer formation requires the amino-terminal membrane-anchoring domain of TatA. According to circular dichroism spectroscopy, approximately half of the TatA polypeptide forms α-helical secondary structure in both detergent solution and proteoliposomes. An expressed construct without the transmembrane segment is largely unstructured in aqueous solution but is able to insert into phospholipid monolayers and interacts with membrane bilayers. Protease accessibility experiments indicate that the extramembranous region of TatA is located at the cytoplasmic face of the cell membrane.
Original languageEnglish
Pages (from-to)13690-13697
Number of pages8
JournalBiochemistry
Volume41
Issue number46
Early online date23 Oct 2002
DOIs
Publication statusPublished - 1 Nov 2002

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