Structure of the membrane protein FhaC: a member of the Omp85-TpsB transporter superfamily.
In Gram-negative bacteria and eukaryotic organelles, beta-barrel proteins of the outer membrane protein 85-two-partner secretion B (Omp85-TpsB) superfamily are essential components of protein transport machineries. The TpsB transporter FhaC mediates the secretion of Bordetella pertussis filamentous hemagglutinin (FHA). We report the 3.15 A crystal structure of FhaC. The transporter comprises a 16-stranded beta barrel that is occluded by an N-terminal alpha helix and an extracellular loop and a periplasmic module composed of two aligned polypeptide-transport-associated (POTRA) domains. Functional data reveal that FHA binds to the POTRA 1 domain via its N-terminal domain and likely translocates the adhesin-repeated motifs in an extended hairpin conformation, with folding occurring at the cell surface. General features of the mechanism obtained here are likely to apply throughout the superfamily.
Clantin
Bernard
B
UMR8161 CNRS, Institut de Biologie de Lille, Université de Lille 1, Université de Lille 2, 1 rue du Prof. Calmette, F-59021 Lille cedex, France.
Delattre
Anne-Sophie
AS
Rucktooa
Prakash
P
Saint
Nathalie
N
Méli
Albano C
AC
Locht
Camille
C
Jacob-Dubuisson
Françoise
F
Villeret
Vincent
V
D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001886:Bordetella pertussis / Q000737:chemistry* / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D018360:Crystallography, X-Ray; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011487:Protein Conformation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D010566:Virulence Factors, Bordetella / Q000737:chemistry / Q000378:metabolism*
D018829:Adhesins, Bacterial; D001425:Bacterial Outer Membrane Proteins; D008051:Lipid Bilayers; D026901:Membrane Transport Proteins; D010566:Virulence Factors, Bordetella; C098052:fhaC protein, Bordetella pertussis; C065273:filamentous hemagglutinin adhesin, Bordetella pertussis