Molecular analysis of the flagellar switch protein FliM of Salmonella typhimurium

Sockett, Hilary; Yamaguchi, Shigeru; Kihara, May; Irikura, Vera M.; Macnab, Robert M.

doi:10.1128/jb.174.3.793-806.1992

Cited by 184 publications

(241 citation statements)

References 36 publications

Supporting

Mentioning

226

Contrasting

Order By: Relevance

“…As shown in the CheY alignment in Fig. 2, 7 of 10 residues which are thought to be involved in docking to the motor polypeptides FliM and FliG (37) are not conserved between CheAY and CheY. Indeed, half of the amino acid substitutions involve alterations in hydrophobicity or charge.…”

Section: Discussionmentioning

confidence: 99%

“…While we have no direct evidence for separate motors in R. centenum, we have observed that the polar and lateral flagella are composed of different flagellin and basal ring subunits (16,32). Evidence for different specificities of the R. centenum CheY homologs to the motor complex can also be obtained by inspection of the motor docking domains that have been identified by mutational and crystallographic analyses of CheY homologs from E. coli and S. typhimurium (31,37,38,43). As shown in the CheY alignment in Fig.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Analysis of a chemotaxis operon from Rhodospirillum centenum

Jiang

Bauer

1997

J Bacteriol

View full text Add to dashboard Cite

A chemotaxis gene cluster from the photosynthetic bacterium Rhodospirillum centenum has been cloned, sequenced, and analyzed for the control of transcription during swimmer-to-swarm cell differentiation. The first gene of the operon (cheAY) codes for a large 108-kDa polypeptide with an amino-terminal domain that is homologous to CheA and a carboxyl terminus that is homologous to CheY. cheAY is followed by cheW, an additional homolog of cheY, cheB, and cheR. Sequence analysis indicated that all of the che genes are tightly compacted with the same transcriptional polarity, suggesting that they are organized in an operon. Cotranscription of the che genes was confirmed by demonstrating through Western blot analysis that insertion of a polar spectinomycin resistance gene in cheAY results in loss of cheR expression. The promoter for the che operon was mapped by primer extension analysis as well as by the construction of promoter reporter plasmids that include several deletion intervals. This analysis indicated that the R. centenum che operon utilizes two promoters; one exhibits a 70 -like sequence motif, and the other exhibits a 54 -like motif. Expression of the che operon is shown to be relatively constant for swimmer cells which contain a single flagellum and for swarm cells that contain multiple lateral flagella.More than a century ago, Engelmann (7) observed that when purple sulfur photosynthetic bacteria of the genus Chromatium were illuminated with a broad spectrum of light, the cells accumulated at wavelengths that corresponded to the in vivo absorption peaks of the cells. A more accurate description of this phenomenon is that when smooth-swimming cells migrate into a dark region (or into regions of the spectrum where wavelengths are not absorbed by photopigments), they either tumble or reverse the direction of movement, depending on the species. The phenomenon has been termed a scotophobic (fear of darkness) response since the cells exhibit an aversion to darkness rather than a specific affinity for light (12,29). Since a reduction in light intensity causes a tumbling/reversal response, the mechanism of moving through an increasing gradient of light intensity appears to involve a directed "random walk" such that the length of smooth swimming is longer when cells are going up a light gradient than when they are going down. Superficially, this process is not unlike the wellcharacterized bacterial "trial-and-error" walking up a chemical gradient that is mediated by chemoreceptors and the Che protein phosphorylation cascade (2, 40).The mechanism whereby a reduction in light intensity causes a tumbling/reversal response is still unclear. However, recent work has revealed that a functioning photosynthetic apparatus is required for photosensory perception (3). In addition, chemical inhibition of electron carrier components such as the cytochrome bc 1 complex, are incapable of light perception (4). These results have led to the current dogma that the scotophobic response is mediated by the perception of a sudden decre...

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Analysis of a chemotaxis operon from Rhodospirillum centenum

Jiang

Bauer

1997

J Bacteriol

View full text Add to dashboard Cite

show abstract

“…In the chemotaxis system, bias for clockwise versus counter-clockwise motor rotation is controlled by interactions of phosphoCheY with the flagellar switch protein FliM. Many, if not all mutations in FliM that suppress mutations in CheY are thought to adjust the bias of the switch rather than restore normal interactions with mutant CheY (41,42). The indirect effect of these suppressor mutations in FliM is analogous to the effect of hinge mutations in GroEL that compensate for strong or weak binding by mobile loop mutants in Gp31.…”

Section: Amino Acid Substitutions In the Groel Hinge Regions Affect Lmentioning

confidence: 99%

Compensatory Changes in GroEL/Gp31 Affinity as a Mechanism for Allele-specific Genetic Interaction

Richardson

Vies

Taher

et al. 1999

Journal of Biological Chemistry

View full text Add to dashboard Cite

Previous work has shown that the GroEL-GroES interaction is primarily mediated by the GroES mobile loop. In bacteriophage T4 infection, GroES is substituted by the gene 31-encoded cochaperonin, Gp31. Using a genetic selection scheme, we have identified a new set of mutations in gene 31 that affect interaction with GroEL; all mutations result in changes in the mobile loop of Gp31. Biochemical analyses reveal that the mobile loop mutations alter the affinity between Gp31 and GroEL, most likely by modulating the stability of the GroEL-bound hairpin conformation of the mobile loop. Surprisingly, mutations in groEL that display allele-specific interactions with mutations in gene 31 alter residues in the GroEL intermediate domain, distantly located from the mobile loop binding site. The observed patterns of genetic and biochemical interaction between GroES or Gp31 and GroEL point to a mechanism of genetic allele specificity based on compensatory changes in affinity of the protein-protein interaction. Mutations studied in this work indirectly alter affinity by modulating a folding transition in the Gp31 mobile loop or by modulating a hinged conformational change in GroEL.

show abstract

“…The purified protein complex appears to consist of PomA and PomB and contains neither MotX nor MotY. The PomA/B protein, reconstituted into proteoliposomes, catalyzed 22 …”

mentioning

confidence: 99%

Functional Reconstitution of the Na+-driven Polar Flagellar Motor Component of Vibrio alginolyticus

Sato

Homma

2000

Journal of Biological Chemistry

144

View full text Add to dashboard Cite

The bacterial flagellar motor is a molecular machine that couples the influx of specific ions to the generation of the force necessary to drive rotation of the flagellar filament. Four integral membrane proteins, PomA, PomB, MotX, and MotY, have been suggested to be directly involved in torque generation of the Na ؉ -driven polar flagellar motor of Vibrio alginolyticus. In the present study, we report the isolation of the functional component of the torque-generating unit. The purified protein complex appears to consist of PomA and PomB and contains neither MotX nor MotY. The PomA/B protein, reconstituted into proteoliposomes, catalyzed 22 Na؉ influx in response to a potassium diffusion potential. Sodium uptake was abolished by the presence of Li ؉ ions and phenamil, a sodium channel blocker. This is the first demonstration of a purification and functional reconstitution of the bacterial flagellar motor component involved in torque generation. In addition, this study demonstrates that the Na ؉ -driven motor component, PomA and PomB, forms the Na ؉ -conducting channel.

show abstract

Molecular analysis of the flagellar switch protein FliM of Salmonella typhimurium

Cited by 184 publications

References 36 publications

Analysis of a chemotaxis operon from Rhodospirillum centenum

Analysis of a chemotaxis operon from Rhodospirillum centenum

Compensatory Changes in GroEL/Gp31 Affinity as a Mechanism for Allele-specific Genetic Interaction

Functional Reconstitution of the Na+-driven Polar Flagellar Motor Component of Vibrio alginolyticus

Contact Info

Product

Resources

About