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MotX and MotY, specific components of the sodium‐driven flagellar motor, colocalize to the outer membrane in Vibrio alginolyticus
Author(s) -
Okabe Mayuko,
Yakushi Toshiharu,
Kojima Masaru,
Homma Michio
Publication year - 2002
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.2002.03142.x
Subject(s) - vibrio alginolyticus , bacterial outer membrane , biology , flagellum , membrane , cytoplasm , periplasmic space , membrane protein , inner membrane , colocalization , microbiology and biotechnology , vibrio , biophysics , biochemistry , bacteria , escherichia coli , genetics , gene
Summary Rotation of the sodium‐driven polar flagella of Vibrio alginolyticus requires four motor proteins: PomA, PomB, MotX and MotY. MotX and MotY, which are unique components of the sodium‐driven motor of Vibrio , have been believed to be localized in the inner (cytoplasmic) membrane via their N‐terminal hydrophobic segments. Here we show that MotX and MotY colocalize to the outer membrane. Both proteins, when expressed together, were detected in the outer membrane fraction separated by sucrose density gradient centrifugation. As mature MotX and MotY proteins do not have N‐terminal hydrophobic segments, the N‐termini of the primary translation products must have signal sequences that are removed upon translocation across the inner membrane. Moreover, MotX and MotY require each other for efficient localization to the outer membrane. Based on these lines of evidence, we propose that MotX and MotY form a complex in the outer membrane. This is the first case that describes motor proteins function in the outer membrane for flagellar rotation.