Structural insights into serine-rich fimbriae from Gram-positive bacteria.
The serine-rich repeat family of fimbriae play important roles in the pathogenesis of streptococci and staphylococci. Despite recent attention, their finer structural details and precise adhesion mechanisms have yet to be determined. Fap1 (Fimbriae-associated protein 1) is the major structural subunit of serine-rich repeat fimbriae from Streptococcus parasanguinis and plays an essential role in fimbrial biogenesis, adhesion, and the early stages of dental plaque formation. Combining multidisciplinary, high resolution structural studies with biological assays, we provide new structural insight into adhesion by Fap1. We propose a model in which the serine-rich repeats of Fap1 subunits form an extended structure that projects the N-terminal globular domains away from the bacterial surface for adhesion to the salivary pellicle. We also uncover a novel pH-dependent conformational change that modulates adhesion and likely plays a role in survival in acidic environments.
Ramboarina
Stéphanie
S
Department of Biological Sciences, Centre for Structural Biology, Imperial College London, South Kensington, London SW7 2AZ, United Kingdom.
Garnett
James A
JA
Zhou
Meixian
M
Li
Yuebin
Y
Peng
Zhixiang
Z
Taylor
Jonathan D
JD
Lee
Wei-Chao
WC
Bodey
Andrew
A
Murray
James W
JW
Alguel
Yilmaz
Y
Bergeron
Julien
J
Bardiaux
Benjamin
B
Sawyer
Elizabeth
E
Isaacson
Rivka
R
Tagliaferri
Camille
C
Cota
Ernesto
E
Nilges
Michael
M
Simpson
Peter
P
Ruiz
Teresa
T
Wu
Hui
H
Matthews
Stephen
S
D000595:Amino Acid Sequence; D001422:Bacterial Adhesion / Q000502:physiology*; D018360:Crystallography, X-Ray; D036781:Fimbriae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D010861:Fimbriae, Bacterial / Q000737:chemistry / Q000648:ultrastructure*; D006094:Gram-Positive Bacteria / Q000737:chemistry / Q000235:genetics / Q000648:ultrastructure*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D053838:Scattering, Small Angle; D012694:Serine / Q000235:genetics*; D013291:Streptococcus / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure
C403708:fap1 protein, Streptococcus; D036781:Fimbriae Proteins; D012694:Serine