title: The action of cardiolipin on the bacterial translocon.
abstract: Cardiolipin is an ever-present component of the energy-conserving inner membranes of bacteria and mitochondria. Its modulation of the structure and dynamism of the bilayer impacts on the activity of their resident proteins, as a number of studies have shown. Here we analyze the consequences cardiolipin has on the conformation, activity, and localization of the protein translocation machinery. Cardiolipin tightly associates with the SecYEG protein channel complex, whereupon it stabilizes the dimer, creates a high-affinity binding surface for the SecA ATPase, and stimulates ATP hydrolysis. In addition to the effects on the structure and function, the subcellular distribution of the complex is modified by the cardiolipin content of the membrane. Together, the results provide rare and comprehensive insights into the action of a phospholipid on an essential transport complex, which appears to be relevant to a broad range of energy-dependent reactions occurring at membranes.
authors.affiliation: Department of Biochemistry, University of Bristol, University Walk, Bristol, BS8 1TD, United Kingdom.
authors.forename: Vicki A M
authors.initials: VA
authors.lastname: Gold
authors.forename: Alice
authors.initials: A
authors.lastname: Robson
authors.forename: Huan
authors.initials: H
authors.lastname: Bao
authors.forename: Tatyana
authors.initials: T
authors.lastname: Romantsov
authors.forename: Franck
authors.initials: F
authors.lastname: Duong
authors.forename: Ian
authors.initials: I
authors.lastname: Collinson
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D020240:Apraxia, Ideomotor; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002308:Cardiolipins / Q000378:metabolism / Q000494:pharmacology*; D004926:Escherichia coli / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005456:Fluorescent Dyes; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D046912:Multiprotein Complexes; D055550:Protein Stability / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects*; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
chemical_list: D001426:Bacterial Proteins; D002308:Cardiolipins; D029968:Escherichia coli Proteins; D005456:Fluorescent Dyes; D026901:Membrane Transport Proteins; D046912:Multiprotein Complexes; D000069816:SEC Translocation Channels; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins