title: Extended sugar slide function for the periplasmic coiled coil domain of ScrY.
abstract: Several bacterial outer membrane proteins have a periplasmic extension whose structure and function remain elusive. Here, the structure/function relationship of the N-terminal periplasmic domain of the sucrose-specific outer membrane channel ScrY was investigated. Circular dichroism and analytical centrifugation demonstrated that the N-terminal domain formed a parallel, three-stranded coiled coil. When this domain was fused to the maltose-specific channel LamB, permeation of maltooligosaccharides in liposomes increased with increasing sugar chain length whereas wild-type LamB showed the opposite effect. Current fluctuation analysis demonstrated increased off-rates for sugar transport through the fusion protein. Moreover, equilibrium dialysis showed an affinity of sucrose for the isolated N-terminal peptide. Together these results demonstrate a novel function for coiled coil domains, operating as an extended sugar slide.
authors.affiliation: Department of Biophysical Chemistry, Biozentrum University of Basle, Klingelbergstrasse 70, Basel, CH-4056, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Dumas
authors.forename: S
authors.initials: S
authors.lastname: Frank
authors.forename: R
authors.initials: R
authors.lastname: Koebnik
authors.forename: E
authors.initials: E
authors.lastname: Maillet
authors.forename: A
authors.initials: A
authors.lastname: Lustig
authors.forename: P
authors.initials: P
authors.lastname: Van Gelder
mesh_terms: D000478:Alkylation; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D001692:Biological Transport; D050260:Carbohydrate Metabolism; D002942:Circular Dichroism; D003956:Dialysis; D007700:Kinetics; D008081:Liposomes / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D009994:Osmolar Concentration; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D019897:Periplasm / Q000378:metabolism*; D018272:Porins / Q000737:chemistry* / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D011991:Receptors, Virus / Q000737:chemistry / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D013329:Structure-Activity Relationship; D013395:Sucrose / Q000378:metabolism; D013816:Thermodynamics; D014461:Ultracentrifugation
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D008081:Liposomes; D009844:Oligosaccharides; D010446:Peptide Fragments; D018272:Porins; D011991:Receptors, Virus; D011993:Recombinant Fusion Proteins; C079242:ScrY protein, bacteria; C021705:maltooligosaccharides; C016532:maltoporins; D013395:Sucrose