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A mutation leading to super-assembly of twin-arginine translocase (Tat) protein complexes.

Patel, Roshani, Vasilev, Cvetelin, Beck, Daniel, Monteferrante, Carmine G, van Dijl, Jan Maarten, Hunter, C Neil, Smith, Corinne, Robinson, Colin (2014) A mutation leading to super-assembly of twin-arginine translocase (Tat) protein complexes. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research, 1843 (9). pp. 1978-86. ISSN 0006-3002. (doi:10.1016/j.bbamcr.2014.05.009) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Official URL
http://dx.doi.org/10.1016/j.bbamcr.2014.05.009

Abstract

The Tat system transports folded proteins across the bacterial plasma membrane. The mechanism is believed to involve coalescence of a TatC-containing unit with a separate TatA complex, but the full translocation complex has never been visualised and the assembly process is poorly defined. We report the analysis of the Bacillus subtilis TatAyCy system, which occurs as separate TatAyCy and TatAy complexes at steady state, using single-particle electron microscopy (EM) and advanced atomic force microscopy (AFM) approaches. We show that a P2A mutation in the TatAy subunit leads to apparent super-assembly of Tat complexes. Purification of TatCy-containing complexes leads to a large increase in the TatA:TatC ratio, suggesting that TatAy(P2A) complexes may have attached to the TatAyCy complex. EM and AFM analyses show that the wild-type TatAyCy complex purifies as roughly spherical complexes of 9-16nm diameter, whereas the P2A mutation leads to accumulation of large (up to 500nm long) fibrils that are chains of numerous complexes. Time lapsed AFM imaging, recorded on fibrils under liquid, shows that they adopt a variety of tightly curved conformations, with radii of curvature of 10-12nm comparable to the size of single TatAy(P2A) complexes. The combined data indicate that the mutation leads to super-assembly of TatAy(P2A) complexes and we propose that an individual TatAy(P2A) complex assembles initially with a TatAy(P2A)Cy complex, after which further TatAy(P2A) complexes attach to each other. The data further suggest that the N-terminal extracytoplasmic domain of TatAy plays an essential role in Tat complex interactions.

Item Type: Article
DOI/Identification number: 10.1016/j.bbamcr.2014.05.009
Subjects: Q Science > QH Natural history > QH301 Biology
Divisions: Faculties > Sciences > School of Biosciences
Depositing User: Colin Robinson
Date Deposited: 27 Jan 2015 12:13 UTC
Last Modified: 29 May 2019 14:08 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46915 (The current URI for this page, for reference purposes)
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