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Structure-function studies of the Tat protein translocation channel

ReferenceBB/C516144/1
Principal Investigator / Supervisor Professor Benjamin Berks
Co-Investigators /
Co-Supervisors
Professor Tracy Palmer
Institution University of Oxford
DepartmentBiochemistry
Funding typeResearch
Value (£) 110,885
StatusCompleted
TypeResearch Grant
Start date 01/01/2006
End date 31/12/2008
Duration36 months

Abstract

The membrane proteins TatA, TatB and TatC are the essential components of the Tat transport pathway. TatA and TatBC form separate, highly oligomeric, complexes. The TatBC complex functions as a receptor for the substrate protein. TatA is proposed to form the transmembrane protein translocation channel. This suggestion is supported by our recent low resolution structure of the TatA complex, obtained by negative stain electron microscopy, which shows a variable-diameter ring occluded at one end by a lid structure. This project aims to: (a) continue our studies of the structures of the Tat complexes by electron microscopy. Obtain structures for the TatBC complex by particle electron microscopy methods. Correlate structural features of the TatA complex with protein domains by truncation analysis. Produce higher resolution structures of TatA using single particle cryo-electron microscopy. (b) Carry out a multidisciplinary programme of research to test, exploit and expand the structural and mechanistic insights arising from our low resolution structure of the TatA complex. We will: Test models of channel operation by assessing the oligomeric state of native TatA molecules and examining whether TatA complexes exhibit transport-dependent exchange of TatA protomers. Assess using electron microscopy, atomic force microscopy and electrophysiological techniques whether the TatA complex contains an aqueous channel in the native membrane environment. Attempt to identify regions of the TatA protein that must move to allow Tat transport to occur. To do this we will analyse the effects of introduced disulfide bonds (identified in other work) on in vitro protein transport. Joint with BB/C516179/1

Summary

unavailable
Committee Closed Committee - Biomolecular Sciences (BMS)
Research TopicsMicrobiology, Structural Biology
Research PriorityX – Research Priority information not available
Research Initiative X - not in an Initiative
Funding SchemeX – not Funded via a specific Funding Scheme
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