Structure of TatA paralog, TatE, suggests a structurally homogeneous form of Tat protein translocase that transports folded proteins of differing diameter
Baglieri, J., Beck, D., Vasisht, N., Smith, Corinne J. and Robinson, Colin. (2012) Structure of TatA paralog, TatE, suggests a structurally homogeneous form of Tat protein translocase that transports folded proteins of differing diameter. Journal of Biological Chemistry, Vol.287 (No.10). pp. 7335-7344. ISSN 0021-9258Full text not available from this repository.
Official URL: http://dx.doi.org/10.1074/jbc.M111.326355
The twin-arginine translocation (Tat) system transports folded proteins across bacterial and plant thylakoid membranes. Most current models for the translocation mechanism propose the coalescence of a substrate-binding TatABC complex with a separate TatA complex. In Escherichia coli, TatA complexes are widely believed to form the translocation pore, and the size variation of TatA has been linked to the transport of differently sized substrates. Here, we show that the TatA paralog TatE can substitute for TatA and support translocation of Tat substrates including AmiA, AmiC, and TorA. However, TatE is found as much smaller, discrete complexes. Gel filtration and blue native electrophoresis suggest sizes between ∼50 and 110 kDa, and single-particle processing of electron micrographs gives size estimates of 70-90 kDa. Three-dimensional models of the two principal TatE complexes show estimated diameters of 6-8 nm and potential clefts or channels of up to 2.5nmdiameter. The ability of TatE to support translocation of the 90-kDa TorA protein suggests alternative translocation models in which single TatA/E complexes do not contribute the bulk of the translocation channel. The homogeneity of both theTatABCand the TatE complexes further suggests that a discrete Tat translocase can translocate a variety of substrates, presumably through the use of a flexible channel. The presence and possible significance of double- or triple-ring TatE forms is discussed. © 2012 by The American Society for Biochemistry and Molecular Biology, Inc.
|Item Type:||Journal Article|
|Subjects:||Q Science > Q Science (General)|
|Divisions:||Faculty of Science > Life Sciences (2010- )|
|Journal or Publication Title:||Journal of Biological Chemistry|
|Publisher:||American Society for Biochemistry and Molecular Biology|
|Official Date:||2 March 2012|
|Page Range:||pp. 7335-7344|
|Access rights to Published version:||Restricted or Subscription Access|
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