Dataset Information

Functional chimeras of flagellar stator proteins between E. coli MotB and Vibrio PomB at the periplasmic region in Vibrio or E. coli.

ABSTRACT: The bacterial flagellar motor has a stator and a rotor. The stator is composed of two membrane proteins, MotA and MotB in Escherichia coli and PomA and PomB in Vibrio alginolyticus. The Vibrio motor has a unique structure, the T ring, which is composed of MotX and MotY. Based on the structural information of PomB and MotB, we constructed three chimeric proteins between PomB and MotB, named PotB91 , PotB129, and PotB138 , with various chimeric junctions. When those chimeric proteins were produced with PomA in a ?motAB strain of E. coli or in ?pomAB and ?pomAB ?motX strains of Vibrio, all chimeras were functional in E. coli or Vibrio, either with or without the T ring, although the motilities were very weak in E. coli. Furthermore, we could isolate some suppressors in E. coli and identified the mutation sites on PomA or the chimeric B subunit. The weak function of chimeric PotBs in E. coli is derived mainly from the defect in the rotational switching of the flagellar motor. In addition, comparing the motilities of chimera strains in ?pomAB, PotB138 had the highest motility. The difference between the origin of the ?1 and ?2 helices, E. coli MotB or Vibro PomB, seems to be important for motility in E. coli and especially in Vibrio.

SUBMITTER: Nishino Y

PROVIDER: S-EPMC4398512 | biostudies-literature | 2015 Apr

REPOSITORIES: biostudies-literature

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Functional chimeras of flagellar stator proteins between E. coli MotB and Vibrio PomB at the periplasmic region in Vibrio or E. coli.

Nishino Yuuki Y Onoue Yasuhiro Y Kojima Seiji S Homma Michio M

MicrobiologyOpen 20150129 2

The bacterial flagellar motor has a stator and a rotor. The stator is composed of two membrane proteins, MotA and MotB in Escherichia coli and PomA and PomB in Vibrio alginolyticus. The Vibrio motor has a unique structure, the T ring, which is composed of MotX and MotY. Based on the structural information of PomB and MotB, we constructed three chimeric proteins between PomB and MotB, named PotB91 , PotB129, and PotB138 , with various chimeric junctions. When thos ...[more]

PMID: 25630862

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Project description:Bacterial flagella are the best-known rotational organelles in the biological world. The spiral-shaped flagellar filaments that extend from the cell surface rotate like a screw to create a propulsive force. At the base of the flagellar filament lies a protein motor that consists of a stator and a rotor embedded in the membrane. The stator is composed of two types of membrane subunits, PomA (similar to MotA in Escherichia coli) and PomB (similar to MotB in E. coli), which are energy converters that assemble around the rotor to couple rotation with the ion flow. Recently, stator structures, where two MotB molecules are inserted into the center of a ring made of five MotA molecules, were reported. This structure inspired a model in which the MotA ring rotates around the MotB dimer in response to ion influx. Here, we focus on the Vibrio PomB plug region, which is involved in flagellar motor activation. We investigated the plug region using site-directed photo-cross-linking and disulfide cross-linking experiments. Our results demonstrated that the plug interacts with the extracellular short loop region of PomA, which is located between transmembrane helices 3 and 4. Although the motor stopped rotating after cross-linking, its function recovered after treatment with a reducing reagent that disrupted the disulfide bond. Our results support the hypothesis, which has been inferred from the stator structure, that the plug region terminates the ion influx by blocking the rotation of the rotor as a spanner. IMPORTANCE The biological flagellar motor resembles a mechanical motor. It is composed of a stator and a rotor. The force is transmitted to the rotor by the gear-like stator movements. It has been proposed that the pentamer of MotA subunits revolves around the axis of the B subunit dimer in response to ion flow. The plug region of the B subunit regulates the ion flow. Here, we demonstrated that the ion flow was terminated by cross-linking the plug region of PomB with PomA. These findings support the rotation hypothesis and explain the role of the plug region in blocking the rotation of the stator unit.

Dataset Information

Functional chimeras of flagellar stator proteins between E. coli MotB and Vibrio PomB at the periplasmic region in Vibrio or E. coli.

Publications

Functional chimeras of flagellar stator proteins between E. coli MotB and Vibrio PomB at the periplasmic region in Vibrio or E. coli.

Similar Datasets

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