Two different stator systems drive a single polar flagellum in Shewanella oneidensis MR-1.
The Gram-negative metal ion-reducing bacterium Shewanella oneidensis MR-1 is motile by means of a single polar flagellum. We identified two potential stator systems, PomAB and MotAB, each individually sufficient as a force generator to drive flagellar rotation. Physiological studies indicate that PomAB is sodium-dependent while MotAB is powered by the proton motive force. Flagellar function mainly depends on the PomAB stator; however, the presence of both stator systems under low-sodium conditions results in a faster swimming phenotype. Based on stator homology analysis we speculate that MotAB has been acquired by lateral gene transfer as a consequence of adaptation to a low-sodium environment. Expression analysis at the single cell level showed that both stator systems are expressed simultaneously. An active PomB-mCherry fusion protein effectively localized to the flagellated cell pole in 70-80% of the population independent of sodium concentrations. In contrast, polar localization of MotB-mCherry increased with decreasing sodium concentrations. In the absence of the Pom stator, MotB-mCherry localized to the flagellated cell pole independently of the sodium concentration but was rapidly displaced upon expression of PomAB. We propose that selection of the stator occurs at the level of protein localization in response to sodium concentrations.
Paulick
Anja
A
Department of Ecophysiology, Max-Planck-Institut für Terrestrische Mikrobiologie, Marburg, Germany.
Koerdt
Andrea
A
Lassak
Jürgen
J
Huntley
Stuart
S
Wilms
Ina
I
Narberhaus
Franz
F
Thormann
Kai M
KM
D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics; D005407:Flagella / Q000235:genetics / Q000378:metabolism*; D005816:Genetic Complementation Test; D020409:Molecular Motor Proteins / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017384:Sequence Deletion; D020592:Shewanella / Q000235:genetics / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D013379:Substrate Specificity; D014158:Transcription, Genetic
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D020409:Molecular Motor Proteins; C063010:MotA protein, Bacteria; C064779:MotB protein, Bacteria; C103352:PomA protein, bacteria; C103353:PomB protein, bacteria; D012964:Sodium