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Title: Mechanism of Protein Transport on the Twin Arginine Translocation Pathway

Abstract

Objectives: The research objectives of this proposal are to further explore the mechanism of protein translocation on the Tat pathway. We are developing evidence for a previously undescribed model of protein transport through temporary defects in the membrane bilayer that are formed in response to critical positioning of the subunits of the Tat translocation machinery and substrate protein, and energization of the membrane with a protonmotive force. We will test crucial tenets of this mechanism, including an increase in the lipid flip-flop rate in membranes actively translocating Tat substrates, fusagenic, lysogenic and flippase properties of subunits of the Tat machinery, and effects of the hydrophobic mismatch in the translocon subunits on protein transport. We will also undertake a new collaboration with Professor Igor Vorobyov at UC-Davis to perform Molecular Dynamics calculations of these interactions. Finally, we will continue our efforts to reconstitute Tat transport in artificial proteoliposomes, and undertake a new collaboration with Professor Igor Vorobyov to perform Molecular Dynamics calculations Methods: To realize these objectives we will perform in vitro transport reactions with isolated thylakoids, inverted membrane vesicles from E. coli and artificial proteoliposomes consisting of physiological mixtures of bacterial lipids. We will use fluorescence techniques to monitor lipidmore » flip flop rates during protein transport, and to measure flippase and fusagenic activities of individual substrates of the Tat translocon. We will also explore membrane and substrate properties related to Tat transport by molecular dynamics simulations. Impact: The Tat protein transport pathway operates in bacteria, archaea and chloroplasts. In plants it is responsible for the targeting of proteins with crucial roles in the photosynthetic light reactions. Elucidation of the mechanism of Tat protein transport will open new avenues into research designed to improve the efficiency of photosynthesis. This research will potentially direct future research on this pathway toward a fuller understanding of the role of membrane biophysical properties in affecting chloroplast biogenesis and homeostasis.« less

Authors:
ORCiD logo [1]
  1. University of Calfornia, Davis
Publication Date:
Research Org.:
Univ. of California, Davis, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division
OSTI Identifier:
1633086
Report Number(s):
DOE UCD 1
DOE Contract Number:  
SC0017035
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; Chloroplasts, Protein targting

Citation Formats

Theg, Steven. Mechanism of Protein Transport on the Twin Arginine Translocation Pathway. United States: N. p., 2018. Web. doi:10.2172/1633086.
Theg, Steven. Mechanism of Protein Transport on the Twin Arginine Translocation Pathway. United States. https://doi.org/10.2172/1633086
Theg, Steven. Thu . "Mechanism of Protein Transport on the Twin Arginine Translocation Pathway". United States. https://doi.org/10.2172/1633086. https://www.osti.gov/servlets/purl/1633086.
@article{osti_1633086,
title = {Mechanism of Protein Transport on the Twin Arginine Translocation Pathway},
author = {Theg, Steven},
abstractNote = {Objectives: The research objectives of this proposal are to further explore the mechanism of protein translocation on the Tat pathway. We are developing evidence for a previously undescribed model of protein transport through temporary defects in the membrane bilayer that are formed in response to critical positioning of the subunits of the Tat translocation machinery and substrate protein, and energization of the membrane with a protonmotive force. We will test crucial tenets of this mechanism, including an increase in the lipid flip-flop rate in membranes actively translocating Tat substrates, fusagenic, lysogenic and flippase properties of subunits of the Tat machinery, and effects of the hydrophobic mismatch in the translocon subunits on protein transport. We will also undertake a new collaboration with Professor Igor Vorobyov at UC-Davis to perform Molecular Dynamics calculations of these interactions. Finally, we will continue our efforts to reconstitute Tat transport in artificial proteoliposomes, and undertake a new collaboration with Professor Igor Vorobyov to perform Molecular Dynamics calculations Methods: To realize these objectives we will perform in vitro transport reactions with isolated thylakoids, inverted membrane vesicles from E. coli and artificial proteoliposomes consisting of physiological mixtures of bacterial lipids. We will use fluorescence techniques to monitor lipid flip flop rates during protein transport, and to measure flippase and fusagenic activities of individual substrates of the Tat translocon. We will also explore membrane and substrate properties related to Tat transport by molecular dynamics simulations. Impact: The Tat protein transport pathway operates in bacteria, archaea and chloroplasts. In plants it is responsible for the targeting of proteins with crucial roles in the photosynthetic light reactions. Elucidation of the mechanism of Tat protein transport will open new avenues into research designed to improve the efficiency of photosynthesis. This research will potentially direct future research on this pathway toward a fuller understanding of the role of membrane biophysical properties in affecting chloroplast biogenesis and homeostasis.},
doi = {10.2172/1633086},
url = {https://www.osti.gov/biblio/1633086}, journal = {},
number = ,
volume = ,
place = {United States},
year = {2018},
month = {9}
}