Gene Symbol: motA
Description: proton conductor component of flagella motor
Alias: ECK1891, JW1879, flaJ
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Zhou J, Blair D. Residues of the cytoplasmic domain of MotA essential for torque generation in the bacterial flagellar motor. J Mol Biol. 1997;273:428-39 pubmed
    The MotA protein of Escherichia coli is a component of the flagellum that functions, together with MotB, in transmembrane proton conduction. MotA and MotB are believed to form the stator of the flagellar motor...
  2. Reid S, Leake M, Chandler J, Lo C, Armitage J, Berry R. The maximum number of torque-generating units in the flagellar motor of Escherichia coli is at least 11. Proc Natl Acad Sci U S A. 2006;103:8066-71 pubmed
    ..Stator units are composed of the proteins MotA and MotB in proton-driven motors, and they are composed of PomA and PomB in sodium-driven motors...
  3. Saijo Hamano Y, Uchida N, Namba K, Oosawa K. In vitro characterization of FlgB, FlgC, FlgF, FlgG, and FliE, flagellar basal body proteins of Salmonella. J Mol Biol. 2004;339:423-35 pubmed
    ..These results together with other data indicate that all of the ten flagellar axial proteins share structural characteristics and folding dynamics in relation to the mechanism of their self-assembly into the flagellar axial structure. ..
  4. Ridgway H, Silverman M, Simon M. Localization of proteins controlling motility and chemotaxis in Escherichia coli. J Bacteriol. 1977;132:657-65 pubmed
    ..The motA, motB, cheM, and cheD gene products were found to be confined exclusively to the inner cytoplasmic membrane ..
  5. Van Way S, Hosking E, Braun T, Manson M. Mot protein assembly into the bacterial flagellum: a model based on mutational analysis of the motB gene. J Mol Biol. 2000;297:7-24 pubmed
    ..Together with MotA, it comprises the transmembrane channel that delivers protons to the motor...
  6. Garza A, Harris Haller L, Stoebner R, Manson M. Motility protein interactions in the bacterial flagellar motor. Proc Natl Acad Sci U S A. 1995;92:1970-4 pubmed
    Five proteins (MotA, MotB, FliG, FliM, and FliN) have been implicated in energizing flagellar rotation in Escherichia coli and Salmonella typhimurium...
  7. Braun T, Al Mawsawi L, Kojima S, Blair D. Arrangement of core membrane segments in the MotA/MotB proton-channel complex of Escherichia coli. Biochemistry. 2004;43:35-45 pubmed
    The stator of the bacterial flagellar motor is formed from the membrane proteins MotA and MotB, which associate in complexes with stoichiometry MotA(4)MotB(2) (Kojima, S., and Blair, D. F., preceding paper in this issue)...
  8. Yamaguchi S, Aizawa S, Kihara M, Isomura M, Jones C, Macnab R. Genetic evidence for a switching and energy-transducing complex in the flagellar motor of Salmonella typhimurium. J Bacteriol. 1986;168:1172-9 pubmed
    ..This switch complex is probably mounted to the base of the flagellar basal body and, via binding of the CheY and CheZ proteins, receives sensory information and uses it to control flagellar operation. ..
  9. Sowa Y, Rowe A, Leake M, Yakushi T, Homma M, Ishijima A, et al. Direct observation of steps in rotation of the bacterial flagellar motor. Nature. 2005;437:916-9 pubmed
    ..Backwards steps despite the absence of the flagellar switching protein CheY indicate a small change in free energy per step, similar to that of a single ion transit. ..

More Information


  1. Jones C, Macnab R, Okino H, Aizawa S. Stoichiometric analysis of the flagellar hook-(basal-body) complex of Salmonella typhimurium. J Mol Biol. 1990;212:377-87 pubmed
    ..The ring stoichiometries are discussed in light of other information concerning flagellar structure and function. ..
  2. Blair D, Berg H. The MotA protein of E. coli is a proton-conducting component of the flagellar motor. Cell. 1990;60:439-49 pubmed
    A number of mutants of motA, a gene necessary for flagellar rotation in E. coli, were isolated and characterized...
  3. Stader J, Matsumura P, Vacante D, Dean G, Macnab R. Nucleotide sequence of the Escherichia coli motB gene and site-limited incorporation of its product into the cytoplasmic membrane. J Bacteriol. 1986;166:244-52 pubmed
    ..of MotB into the membrane requires the presence of other more hydrophobic components, possibly including the MotA protein or other components of the flagellar motor...
  4. Silverman M, Simon M. Genetic analysis of flagellar mutants in Escherichia coli. J Bacteriol. 1973;113:105-13 pubmed
    ..Genetic analysis of flagellar mutations in region III suggested that the mutations located in cistrons A, B, C, and E are closely linked and mutations in cistrons D and F are closely linked. ..
  5. Wilson M, Macnab R. Overproduction of the MotA protein of Escherichia coli and estimation of its wild-type level. J Bacteriol. 1988;170:588-97 pubmed
    The motA gene of Escherichia coli was placed under the control of a high-level promoter, that of the tryptophan operon of Serratia marcescens...
  6. Garza A, Biran R, Wohlschlegel J, Manson M. Mutations in motB suppressible by changes in stator or rotor components of the bacterial flagellar motor. J Mol Biol. 1996;258:270-85 pubmed
    Five proteins (MotA, MotB, FliG, FliM and FliN) may be involved in energizing flagellar rotation in Escherichia coli...
  7. Blair D, Berg H. Mutations in the MotA protein of Escherichia coli reveal domains critical for proton conduction. J Mol Biol. 1991;221:1433-42 pubmed
    The MotA protein of Escherichia coli is an essential component of the torque-generating units that drive the flagellar rotary motor. A variety of evidence indicates that MotA is involved in transmembrane proton conduction...
  8. Suzuki H, Yonekura K, Murata K, Hirai T, Oosawa K, Namba K. A structural feature in the central channel of the bacterial flagellar FliF ring complex is implicated in type III protein export. J Struct Biol. 1998;124:104-14 pubmed
    ..This suggests that a domain of FliF partially occupies the central channel to be involved in the export and gate mechanism, and the domain changes its conformation depending on the ionic strength. ..
  9. Ryu W, Berry R, Berg H. Torque-generating units of the flagellar motor of Escherichia coli have a high duty ratio. Nature. 2000;403:444-7 pubmed
    ..Rotation of the bacterial flagellar motor is driven by an ensemble of torque-generating units containing the proteins MotA and MotB...
  10. Yuan J, Berg H. Resurrection of the flagellar rotary motor near zero load. Proc Natl Acad Sci U S A. 2008;105:1182-5 pubmed publisher
    ..Torque is generated by the interaction of stator proteins, MotA and MotB, with a rotor protein FliG...
  11. Grünenfelder B, Gehrig S, Jenal U. Role of the cytoplasmic C terminus of the FliF motor protein in flagellar assembly and rotation. J Bacteriol. 2003;185:1624-33 pubmed
    ..These results provide genetic support for a model in which only a short stretch of amino acids at the immediate C terminus of FliF is required for flagellar assembly through stable interaction with the FliG switch protein. ..
  12. Asai Y, Yakushi T, Kawagishi I, Homma M. Ion-coupling determinants of Na+-driven and H+-driven flagellar motors. J Mol Biol. 2003;327:453-63 pubmed
    ..In proton-driven motors, the membrane proteins MotA and MotB interact via their transmembrane regions to form a proton channel...
  13. Kojima S, Blair D. Solubilization and purification of the MotA/MotB complex of Escherichia coli. Biochemistry. 2004;43:26-34 pubmed
    ..The stator of the flagellar motor is formed from the membrane proteins MotA and MotB, which function together to conduct ions across the membrane and couple ion flow to rotation...
  14. Minamino T, Yamaguchi S, Macnab R. Interaction between FliE and FlgB, a proximal rod component of the flagellar basal body of Salmonella. J Bacteriol. 2000;182:3029-36 pubmed
    ..We suggest that FliE subunits constitute a junction zone between the MS ring and the rod and also that the proximal rod structure consists of FlgB subunits. ..
  15. De Wulf P, Kwon O, Lin E. The CpxRA signal transduction system of Escherichia coli: growth-related autoactivation and control of unanticipated target operons. J Bacteriol. 1999;181:6772-8 pubmed
    ..The results suggest that the CpxRA system plays a core role in an extensive stress response network in which the coordination of protein turnover and energy conservation may be the unifying element. ..
  16. Kim E, Price Carter M, Carlquist W, Blair D. Membrane segment organization in the stator complex of the flagellar motor: implications for proton flow and proton-induced conformational change. Biochemistry. 2008;47:11332-9 pubmed publisher
    b>MotA and MotB are membrane proteins that form the stator of the bacterial flagellar motor...
  17. Kutsukake K, Minamino T, Yokoseki T. Isolation and characterization of FliK-independent flagellation mutants from Salmonella typhimurium. J Bacteriol. 1994;176:7625-9 pubmed
    ..On the basis of these results, we discuss the mechanism of suppression of the fliK defects by the flhB mutations and propose a hypothesis on the export switching machinery of the flagellar proteins. ..
  18. Dean G, Macnab R, Stader J, Matsumura P, Burks C. Gene sequence and predicted amino acid sequence of the motA protein, a membrane-associated protein required for flagellar rotation in Escherichia coli. J Bacteriol. 1984;159:991-9 pubmed
    The motA and motB gene products of Escherichia coli are integral membrane proteins necessary for flagellar rotation. We determined the DNA sequence of the region containing the motA gene and its promoter...
  19. Welch M, Oosawa K, Aizawa S, Eisenbach M. Phosphorylation-dependent binding of a signal molecule to the flagellar switch of bacteria. Proc Natl Acad Sci U S A. 1993;90:8787-91 pubmed
    ..This study provides a biochemical demonstration of binding of a signal molecule to the bacterial switch and demonstrates directly that phosphorylation regulates the activity of this molecule. ..
  20. Silverman M, Simon M. Identification of polypeptides necessary for chemotaxis in Escherichia coli. J Bacteriol. 1977;130:1317-25 pubmed
    ..The synthesis of all of these polypeptides is regulated by the same mechanisms that regulate the synthesis of flagellar-related structural components. ..
  21. Sosinsky G, Francis N, DeRosier D, Wall J, Simon M, Hainfeld J. Mass determination and estimation of subunit stoichiometry of the bacterial hook-basal body flagellar complex of Salmonella typhimurium by scanning transmission electron microscopy. Proc Natl Acad Sci U S A. 1992;89:4801-5 pubmed
    ..amp; Aizawa, S.-I. (1990) J. Mol. Biol. 212, 377-387] using quantitative gel electrophoresis. The results of Jones et al., together with ours, account for all proteins in the basal body to within approximately 5% (or 200 kDa). ..
  22. Braun T, Blair D. Targeted disulfide cross-linking of the MotB protein of Escherichia coli: evidence for two H(+) channels in the stator Complex. Biochemistry. 2001;40:13051-9 pubmed
    ..The stator of the flagellar motor is formed from the membrane proteins MotA and MotB, which associate in complexes that contain multiple copies of each protein...
  23. Samatey F, Imada K, Nagashima S, Vonderviszt F, Kumasaka T, Yamamoto M, et al. Structure of the bacterial flagellar protofilament and implications for a switch for supercoiling. Nature. 2001;410:331-7 pubmed
    ..By simulated extension of the protofilament model, we have identified possible switch regions responsible for the bi-stable mechanical switch that generates the 0.8 A difference in repeat distance. ..
  24. Nguyen C, Saier M. Structural and phylogenetic analysis of the MotA and MotB families of bacterial flagellar motor proteins. Res Microbiol. 1996;147:317-32 pubmed
    b>MotA and MotB are two well-characterized proteins in Escherichia coli which are believed to function as the proton channel and the anchor, respectively, of the motor component of the bacterial flagellum...
  25. Gabel C, Berg H. The speed of the flagellar rotary motor of Escherichia coli varies linearly with protonmotive force. Proc Natl Acad Sci U S A. 2003;100:8748-51 pubmed
    ..The present work shows that a linear relation is true more generally, providing an additional constraint on possible motor mechanisms. ..
  26. Cascales E, Lloubes R, Sturgis J. The TolQ-TolR proteins energize TolA and share homologies with the flagellar motor proteins MotA-MotB. Mol Microbiol. 2001;42:795-807 pubmed
    ..and TolR present structural and functional homologies not only to ExbB and ExbD of the TonB system but also with MotA and MotB of the flagellar motor...
  27. Slocum M, Parkinson J. Genetics of methyl-accepting chemotaxis proteins in Escherichia coli: organization of the tar region. J Bacteriol. 1983;155:565-77 pubmed
    ..Restriction endonuclease analyses of phage and plasmid clones indicated that all of the genetic coding capacity in the tar region is now accounted for. ..
  28. Khan S, Dapice M, Reese T. Effects of mot gene expression on the structure of the flagellar motor. J Mol Biol. 1988;202:575-84 pubmed
    ..Simultaneous introduction of the motA and motB genes, led to recovery of both motility and the ring structures but neither gene alone was sufficient...
  29. Thomas D, Morgan D, DeRosier D. Rotational symmetry of the C ring and a mechanism for the flagellar rotary motor. Proc Natl Acad Sci U S A. 1999;96:10134-9 pubmed
    ..Movement results from the swapping of stud-bound levers with M ring-bound levers. The model predicts that both the M and C rings rotate in the same direction but at different speeds. ..
  30. Garza A, Bronstein P, Valdez P, Harris Haller L, Manson M. Extragenic suppression of motA missense mutations of Escherichia coli. J Bacteriol. 1996;178:6116-22 pubmed
    The MotA and MotB proteins are thought to comprise elements of the stator component of the flagellar motor of Escherichia coli...
  31. Mirel D, Lustre V, Chamberlin M. An operon of Bacillus subtilis motility genes transcribed by the sigma D form of RNA polymerase. J Bacteriol. 1992;174:4197-204 pubmed
    ..6-kb transcript contains two open reading frames coding for protein sequences homologous to the Escherichia coli motA and motB gene products, respectively, and ends in a rho-independent termination site...
  32. Leake M, Chandler J, Wadhams G, Bai F, Berry R, Armitage J. Stoichiometry and turnover in single, functioning membrane protein complexes. Nature. 2006;443:355-8 pubmed
    ..04 s(-1): the dwell time of a given stator in the motor is only approximately 0.5 min. This is the first direct measurement of the number and rapid turnover of protein subunits within a functioning molecular machine. ..
  33. Maki S, Vonderviszt F, Furukawa Y, Imada K, Namba K. Plugging interactions of HAP2 pentamer into the distal end of flagellar filament revealed by electron microscopy. J Mol Biol. 1998;277:771-7 pubmed
    ..This also allows us to model the axial domain arrangement of flagellin subunit in the filament. ..
  34. Maki Yonekura S, Yonekura K, Namba K. Domain movements of HAP2 in the cap-filament complex formation and growth process of the bacterial flagellum. Proc Natl Acad Sci U S A. 2003;100:15528-33 pubmed
  35. Yonekura K, Maki S, Morgan D, DeRosier D, Vonderviszt F, Imada K, et al. The bacterial flagellar cap as the rotary promoter of flagellin self-assembly. Science. 2000;290:2148-52 pubmed
    ..This represents one of the most dynamic movements in protein structures. ..
  36. Katayama E, Shiraishi T, Oosawa K, Baba N, Aizawa S. Geometry of the flagellar motor in the cytoplasmic membrane of Salmonella typhimurium as determined by stereo-photogrammetry of quick-freeze deep-etch replica images. J Mol Biol. 1996;255:458-75 pubmed
    ..Various dimensions of the MS ring complex and the C ring projecting from the membrane were determined by digital stereo-photogrammetry, and a three-dimensional model of the total basal structure is presented. ..
  37. Tang H, Braun T, Blair D. Motility protein complexes in the bacterial flagellar motor. J Mol Biol. 1996;261:209-21 pubmed
    ..These are MotA, MotB, FliG, FliM and FliN...
  38. Wood T, Gonzalez Barrios A, Herzberg M, Lee J. Motility influences biofilm architecture in Escherichia coli. Appl Microbiol Biotechnol. 2006;72:361-7 pubmed
    ..JM109, DH5alpha, and MG1655 motA formed intermediate biofilms ( approximately 13 microm thick, 41 to 58% surface coverage)...
  39. Yakushi T, Yang J, Fukuoka H, Homma M, Blair D. Roles of charged residues of rotor and stator in flagellar rotation: comparative study using H+-driven and Na+-driven motors in Escherichia coli. J Bacteriol. 2006;188:1466-72 pubmed
    ..motor has been shown to depend upon electrostatic interactions between charged residues of the stator protein MotA and the rotor protein FliG...
  40. Zhou J, Fazzio R, Blair D. Membrane topology of the MotA protein of Escherichia coli. J Mol Biol. 1995;251:237-42 pubmed
    The MotA protein of Escherichia coli is a component of the flagella that functions together with the MotB protein in transmembrane proton conduction...
  41. Macnab R. How bacteria assemble flagella. Annu Rev Microbiol. 2003;57:77-100 pubmed
    ..Exported substrates diffuse down a narrow channel in the growing structure and assemble at the distal end, often with the help of a capping structure. ..
  42. Zhou J, Sharp L, Tang H, Lloyd S, Billings S, Braun T, et al. Function of protonatable residues in the flagellar motor of Escherichia coli: a critical role for Asp 32 of MotB. J Bacteriol. 1998;180:2729-35 pubmed
    ..The proteins most closely involved in motor rotation are MotA, MotB, and FliG...
  43. Hasegawa K, Yamashita I, Namba K. Quasi- and nonequivalence in the structure of bacterial flagellar filament. Biophys J. 1998;74:569-75 pubmed
  44. Hosking E, Manson M. Clusters of charged residues at the C terminus of MotA and N terminus of MotB are important for function of the Escherichia coli flagellar motor. J Bacteriol. 2008;190:5517-21 pubmed publisher
    b>MotA contains a conserved C-terminal cluster of negatively charged residues, and MotB contains a conserved N-terminal cluster of positively charged residues...
  45. Hosking E, Vogt C, Bakker E, Manson M. The Escherichia coli MotAB proton channel unplugged. J Mol Biol. 2006;364:921-37 pubmed
    The MotA and MotB proteins of Escherichia coli serve two functions. The MotA4MotB2 complex attaches to the cell wall via MotB to form the stator of the flagellar motor...
  46. Chun S, Parkinson J. Bacterial motility: membrane topology of the Escherichia coli MotB protein. Science. 1988;239:276-8 pubmed
    ..Protease treatment of MotB in spheroplasts confirmed this view. The simple transmembrane organization of MotB is difficult to reconcile with a role as a proton conductor. ..
  47. Suzuki H, Yonekura K, Namba K. Structure of the rotor of the bacterial flagellar motor revealed by electron cryomicroscopy and single-particle image analysis. J Mol Biol. 2004;337:105-13 pubmed
  48. Zhou J, Lloyd S, Blair D. Electrostatic interactions between rotor and stator in the bacterial flagellar motor. Proc Natl Acad Sci U S A. 1998;95:6436-41 pubmed
    ..Mutational studies of the rotor protein FliG and the stator protein MotA showed that both proteins contain charged residues essential for motor rotation...
  49. Pratt L, Kolter R. Genetic analysis of Escherichia coli biofilm formation: roles of flagella, motility, chemotaxis and type I pili. Mol Microbiol. 1998;30:285-93 pubmed
    ..In light of the observations presented here, a working model is discussed that describes the roles of both motility and type I pili in biofilm development. ..
  50. Braun V, Herrmann C. Point mutations in transmembrane helices 2 and 3 of ExbB and TolQ affect their activities in Escherichia coli K-12. J Bacteriol. 2004;186:4402-6 pubmed
    ..E176 and T148 are strictly conserved in ExbB and TolQ proteins, and T181 is almost strictly conserved in ExbB, TolQ, and MotA.