title: Polarity and charge of the periplasmic loop determine the YidC and sec translocase requirement for the M13 procoat lep protein.
abstract: During membrane biogenesis, the M13 procoat protein is inserted into the lipid bilayer in a strictly YidC-dependent manner with both the hydrophobic signal sequence and the membrane anchor sequence promoting translocation of the periplasmic loop via a hairpin mechanism. Here, we find that the translocase requirements can be altered for PClep in a predictable manner by changing the polarity and charge of the peptide region that is translocated across the membrane. When the polarity of the translocated peptide region is lowered and the charged residues in this region are removed, translocation of this loop region occurs largely by a YidC- and Sec-independent mechanism. When the polarity is increased to that of the wild-type procoat protein, the YidC insertase is essential for translocation. Further increasing the polarity, by adding charged residues, switches the insertion pathway to a YidC/Sec mechanism. Conversely, we find that increasing the hydrophobicity of the transmembrane segments of PClep can decrease the translocase requirement for translocation of the peptide chain. This study provides a framework to understand why the YidC and Sec machineries exist in parallel and demonstrates that the YidC insertase has a limited capacity to translocate a peptide chain on its own.
authors.affiliation: From the Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210 and.
authors.forename: Raunak
authors.initials: R
authors.lastname: Soman
authors.forename: Jijun
authors.initials: J
authors.lastname: Yuan
authors.forename: Andreas
authors.initials: A
authors.lastname: Kuhn
authors.forename: Ross E
authors.initials: RE
authors.lastname: Dalbey
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D017104:Bacteriophage M13 / Q000235:genetics / Q000378:metabolism; D036022:Capsid Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism* / Q000821:virology; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism / Q000821:virology; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D019897:Periplasm / Q000737:chemistry / Q000378:metabolism; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
chemical_list: D001426:Bacterial Proteins; D036022:Capsid Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; C065493:SecE protein, E coli; C412443:YIDC protein, E coli; C025668:coat protein, Bacteriophage M13; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins
keywords: Bacteriophage; Membrane Biogenesis; Membrane Insertion; Membrane Proteins; Procoat; SecYEG; Secretion; Trafficking; YidC; YidC Determinants