A Link between Integral Membrane Protein Expression and Simulated Integration Efficiency
Integral membrane proteins (IMPs) control the flow of information and nutrients across cell membranes, yet IMP mechanistic studies are hindered by difficulties in expression. We investigate this issue by addressing the connection between IMP sequence and observed expression levels. For homologs of the IMP TatC, observed expression levels vary widely and are affected by small changes in protein sequence. The effect of sequence changes on experimentally observed expression levels strongly correlates with the simulated integration efficiency obtained from coarse-grained modeling, which is directly confirmed using an in vivo assay. Furthermore, mutations that improve the simulated integration efficiency likewise increase the experimentally observed expression levels. Demonstration of these trends in both Escherichia coli and Mycobacterium smegmatis suggests that the results are general to other expression systems. This work suggests that IMP integration is a determinant for successful expression, raising the possibility of controlling IMP expression via rational design.
© 2016 The Authors. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Received 4 January 2016, Revised 9 June 2016, Accepted 16 July 2016, Available online 11 August 2016. Published: August 11, 2016. The authors thank R.C. Van Lehn and D.C. Rees for comments on the manuscript and D. Daley for helpful discussion of Daley et al. (2005). Work in the W.M.C. lab is supported by an NIH Pioneer Award to W. M. C. (5DP1GM105385) and an NIH training grant to S.S.M. (NIH/National Research Service Award (NRSA) training grant 5T32GM07616). Work in the T.F.M. group is supported in part by the Office of Naval Research (N00014-10-1-0884), and computational resources were provided by the National Energy Research Scientific Computing Center (NERSC), a (Department of Energy) DOE Office of Science User Facility (DE-AC02-05CH11231).
Published - 1-s2.0-S2211124716309603-main.pdf
Supplemental Material - mmc1.pdf
Supplemental Material - mmc2_3_.xlsx
Accepted Version - nihms-810488.pdf
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