title: SurA assists the folding of Escherichia coli outer membrane proteins.
abstract: Many proteins require enzymatic assistance in order to achieve a functional conformation. One rate-limiting step in protein folding is the cis-trans isomerization of prolyl residues, a reaction catalyzed by prolyl isomerases. SurA, a periplasmic protein of Escherichia coli, has sequence similarity with the prolyl isomerase parvulin. We tested whether SurA was involved in folding periplasmic and outer membrane proteins by using trypsin sensitivity as an assay for protein conformation. We determined that the efficient folding of three outer membrane proteins (OmpA, OmpF, and LamB) requires SurA in vivo, while the folding of four periplasmic proteins was independent of SurA. We conclude that SurA assists in the folding of certain secreted proteins.
authors.affiliation: Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston MA 02115, USA.
authors.forename: S W
authors.initials: SW
authors.lastname: Lazar
authors.forename: R
authors.initials: R
authors.lastname: Kolter
mesh_terms: D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000187:drug effects / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D008969:Molecular Sequence Data; D019696:Peptidylprolyl Isomerase; D033903:Periplasmic Proteins; D018272:Porins / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D011991:Receptors, Virus / Q000378:metabolism; D012697:Serine Endopeptidases / Q000096:biosynthesis; D014357:Trypsin / Q000494:pharmacology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; D018272:Porins; D011991:Receptors, Virus; C016532:maltoporins; C061682:DegP protease; D012697:Serine Endopeptidases; D014357:Trypsin; C490900:SurA protein, E coli; C098640:periplasmic peptidylprolyl cis-trans isomerase; D019696:Peptidylprolyl Isomerase