Insights into the stator assembly of the Vibrio flagellar motor from the crystal structure of MotY.
Rotation of the sodium-driven polar flagellum of Vibrio alginolyticus requires four motor proteins: PomA, PomB, MotX, and MotY. PomA and PomB form a sodium-ion channel in the cytoplasmic membrane that functions as a stator complex to couple sodium-ion flux with torque generation. MotX and MotY are components of the T-ring, which is located beneath the P-ring of the polar flagellar basal body and is involved in incorporation of the PomA/PomB complex into the motor. Here, we describe the determination of the crystal structure of MotY at 2.9 A resolution. The structure shows two distinct domains: an N-terminal domain (MotY-N) and a C-terminal domain (MotY-C). MotY-N has a unique structure. MotY-C contains a putative peptidoglycan-binding motif that is remarkably similar to those of peptidoglycan-binding proteins, such as Pal and RmpM, but this region is disordered in MotY. Motility assay of cells producing either of the MotY-N and MotY-C fragments and subsequent biochemical analyses indicate that MotY-N is essential for association of the stator units around the rotor, whereas MotY-C stabilizes the association by binding to the peptidoglycan layer. Based on these observations, we propose a model for the mechanism of stator assembly around the rotor.
Kojima
Seiji
S
Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan.
Shinohara
Akari
A
Terashima
Hiroyuki
H
Yakushi
Toshiharu
T
Sakuma
Mayuko
M
Homma
Michio
M
Namba
Keiichi
K
Imada
Katsumi
K
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D018360:Crystallography, X-Ray; D005407:Flagella / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data; D010457:Peptidoglycan / Q000737:chemistry / Q000378:metabolism; D017434:Protein Structure, Tertiary; D044149:Vibrio alginolyticus / Q000378:metabolism* / Q000502:physiology
D001425:Bacterial Outer Membrane Proteins; C088135:MotY protein, Vibrio; D010457:Peptidoglycan