title: Skp is a periplasmic Escherichia coli protein requiring SecA and SecY for export.
abstract: Skp of Escherichia coli (OmpH of Salmonella typhimurium) is a protein whose precise function has been obscured by its ubiquity in a wide range of subcellular fractions such as those containing DNA, ribosomes, and outer membranes. Combining in vitro and in vivo techniques we show that Skp is synthesized as a larger precursor that is processed upon translocation across the plasma membrane. Translocation is dependent on the H(+)-gradient, ATP, SecA, and SecY. Upon cellular subfractionation (avoiding non-specific electrostatic interactions) Skp partitions with beta-lactamase into the fraction of soluble, periplasmic proteins. In the context of the export factor properties of Skp previously demonstrated in vitro it is conceivable that this protein is involved in the later steps of protein translocation across the plasma membrane and/or sorting to the outer membrane.
authors.affiliation: Institute of Biochemistry, University of Freiburg, Germany.
authors.forename: B M
authors.initials: BM
authors.lastname: Thome
authors.forename: M
authors.initials: M
authors.lastname: Müller
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D001693:Biological Transport, Active; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; D011498:Protein Precursors / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D000069816:SEC Translocation Channels; D000081416:SecA Proteins
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D018832:Molecular Chaperones; D011498:Protein Precursors; D000069816:SEC Translocation Channels; C057841:SecY protein, E coli; C072721:Skp protein, E coli; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases; D000081416:SecA Proteins