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New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon

The twin‐arginine protein translocation (Tat) system transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of chloroplasts. The Tat translocation site is transiently assembled by the recruitment of multiple TatA proteins to a substrate‐activated TatBC recept...

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Autores principales: Alcock, Felicity, Berks, Ben C.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10092561/
https://www.ncbi.nlm.nih.gov/pubmed/36151601
http://dx.doi.org/10.1111/mmi.14984
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author Alcock, Felicity
Berks, Ben C.
author_facet Alcock, Felicity
Berks, Ben C.
author_sort Alcock, Felicity
collection PubMed
description The twin‐arginine protein translocation (Tat) system transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of chloroplasts. The Tat translocation site is transiently assembled by the recruitment of multiple TatA proteins to a substrate‐activated TatBC receptor complex in a process requiring the protonmotive force. The ephemeral nature of the Tat translocation site has so far precluded its isolation. We now report that detergent solubilization of membranes during active transport allows the recovery of receptor complexes that are associated with elevated levels of TatA. We apply this biochemical analysis in combination with live cell fluorescence imaging to Tat systems trapped in the assembled state. We resolve sub‐steps in the Tat translocation cycle and infer that TatA assembly precedes the functional interaction of TatA with a polar cluster site on TatC. We observe that dissipation of the protonmotive force releases TatA oligomers from the assembled translocation site demonstrating that the stability of the TatA oligomer does not depend on binding to the receptor complex and implying that the TatA oligomer is assembled at the periphery of the receptor complex. This work provides new insight into the Tat transport cycle and advances efforts to isolate the active Tat translocon.
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spelling pubmed-100925612023-04-13 New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon Alcock, Felicity Berks, Ben C. Mol Microbiol Research Articles The twin‐arginine protein translocation (Tat) system transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of chloroplasts. The Tat translocation site is transiently assembled by the recruitment of multiple TatA proteins to a substrate‐activated TatBC receptor complex in a process requiring the protonmotive force. The ephemeral nature of the Tat translocation site has so far precluded its isolation. We now report that detergent solubilization of membranes during active transport allows the recovery of receptor complexes that are associated with elevated levels of TatA. We apply this biochemical analysis in combination with live cell fluorescence imaging to Tat systems trapped in the assembled state. We resolve sub‐steps in the Tat translocation cycle and infer that TatA assembly precedes the functional interaction of TatA with a polar cluster site on TatC. We observe that dissipation of the protonmotive force releases TatA oligomers from the assembled translocation site demonstrating that the stability of the TatA oligomer does not depend on binding to the receptor complex and implying that the TatA oligomer is assembled at the periphery of the receptor complex. This work provides new insight into the Tat transport cycle and advances efforts to isolate the active Tat translocon. John Wiley and Sons Inc. 2022-10-05 2022-12 /pmc/articles/PMC10092561/ /pubmed/36151601 http://dx.doi.org/10.1111/mmi.14984 Text en © 2022 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd. https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Articles
Alcock, Felicity
Berks, Ben C.
New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon
title New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon
title_full New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon
title_fullStr New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon
title_full_unstemmed New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon
title_short New insights into the Tat protein transport cycle from characterizing the assembled Tat translocon
title_sort new insights into the tat protein transport cycle from characterizing the assembled tat translocon
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10092561/
https://www.ncbi.nlm.nih.gov/pubmed/36151601
http://dx.doi.org/10.1111/mmi.14984
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