The Glove-like Structure of the Conserved Membrane Protein TatC Provides Insight into Signal Sequence Recognition in Twin-Arginine Translocation
Abstract
In bacteria, two signal-sequence-dependent secretion pathways translocate proteins across the cytoplasmic membrane. Although the mechanism of the ubiquitous general secretory pathway is becoming well understood, that of the twin-arginine translocation pathway, responsible for translocation of folded proteins across the bilayer, is more mysterious. TatC, the largest and most conserved of three integral membrane components, provides the initial binding site of the signal sequence prior to pore assembly. Here, we present two crystal structures of TatC from the thermophilic bacteria Aquifex aeolicus at 4.0 Å and 6.8 Å resolution. The membrane architecture of TatC includes a glove-shaped structure with a lipid-exposed pocket predicted by molecular dynamics to distort the membrane. Correlating the biochemical literature to these results suggests that the signal sequence binds in this pocket, leading to structural changes that facilitate higher order assemblies.
Additional Information
© 2013 Elsevier Ltd. Received: November 28, 2012. Revised: February 14, 2013. Accepted: March 7, 2013. Published: April 11, 2013. We are primarily grateful to Susan Lea and Ben Berks, both at the University of Oxford, for collegiality and for sharing their unpublished structure coordinates. We thank Justin W. Chartron for help with data processing and refinement. We thank William A. Goddard III for the use of the Materials and Process Simulation Center computing clusters for MD simulations. We are grateful to the staff at SSRL beamline 12-2 and J. Kaiser for help in data collection. This long-term project has received assistance from too many people to name specifically; therefore, we are grateful to all who have contributed to this project over the years. We thank D. Rees, S. Shan, S. Tanaka, J. Chartron, G. Lin, A. Müller, V. Somalinga, E. Chun, and H. Gristick for comments on the manuscript. We thank J.T. Clemons, O.W. Clemons, and A. Sureshkumar for support. We are grateful to Gordon and Betty Moore for support of the Molecular Observatory at the California Institute of Technology. Operations at SSRL are supported by the U.S. Department of Energy and the National Institutes of Health (NIH). This work was supported by a Searle Scholar fellowship, a Burroughs-Wellcome Fund Career Award, and an NIH Pioneer Award (Grant 1DP1OD008304-01) to W.M.C.Attached Files
Accepted Version - nihms459474.pdf
Supplemental Material - mmc1.pdf
Supplemental Material - mmc2.zip
Files
Additional details
- PMCID
- PMC3653977
- Eprint ID
- 38950
- DOI
- 10.1016/j.str.2013.03.004
- Resolver ID
- CaltechAUTHORS:20130614-150529575
- Gordon and Betty Moore Foundation
- Department of Energy (DOE)
- NIH
- Searle Scholars Program
- Burroughs-Wellcome Fund
- NIH
- 1DP1OD008304-01
- Created
-
2013-06-18Created from EPrint's datestamp field
- Updated
-
2021-11-09Created from EPrint's last_modified field