title: Role of the N-terminal signal peptide in the membrane insertion of Aquifex aeolicus F1F0 ATP synthase c-subunit.
abstract: Rotary ATPases are membrane protein complexes that couple ATP hydrolysis to ion translocation across the membrane. Overall, they are evolutionarily well conserved, but the N-terminal segments of their rotary subunits (c-subunits) possess different lengths and levels of hydrophobicity across species. By analyzing the N-terminal variability, we distinguish four phylogenetic groups of c-subunits (groups 1-4). We characterize a member of group 2, the c-subunit from Aquifex aeolicus F1F0 ATP synthase, both in native cells and in a heterologous expression system. We demonstrate that its N-terminal segment forms a signal peptide with signal recognition particle (SRP) recognition features and is obligatorily required for membrane insertion. Based on our study and on previous characterizations of c-subunits from other organisms, we propose that c-subunits follow different membrane insertion pathways.
authors.affiliation: Max Planck Institute of Biophysics, Department of Molecular Membrane Biology, Frankfurt am Main, Germany.
authors.forename: Chunli
authors.initials: C
authors.lastname: Zhang
authors.forename: Marco
authors.initials: M
authors.lastname: Marcia
authors.forename: Julian D
authors.initials: JD
authors.lastname: Langer
authors.forename: Guohong
authors.initials: G
authors.lastname: Peng
authors.forename: Hartmut
authors.initials: H
authors.lastname: Michel
mesh_terms: D000595:Amino Acid Sequence; D001419:Bacteria; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D017124:Conserved Sequence; D004926:Escherichia coli; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism*; D021381:Protein Transport; D006180:Proton-Translocating ATPases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D021382:Protein Sorting Signals; D021122:Protein Subunits; D006180:Proton-Translocating ATPases
keywords: energy conservation; membrane insertion; membrane topology; rotary ATPases; signal peptide