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Identification of a fourth cheY gene in Rhodobacter sphaeroides and interspecies interaction within the bacterial chemotaxis signal transduction pathway
Author(s) -
Shah Deepan S. H.,
Porter Steven L.,
Harris Daniel C.,
Wadhams George H.,
Hamblin Paul A.,
Armitage Judith P.
Publication year - 2000
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.1365-2958.2000.01680.x
Subject(s) - rhodobacter sphaeroides , biology , chemotaxis , histidine kinase , mutant , escherichia coli , signal transduction , swarming (honey bee) , flagellum , biochemistry , microbiology and biotechnology , gene , receptor , photosynthesis
The Escherichia coli chemotaxis signal transduction pathway has: CheA, a histidine protein kinase; CheW, a linker between CheA and sensory proteins; CheY, the effector; and CheZ, a signal terminator. Rhodobacter sphaeroides has multiple copies of these proteins (2 × CheA, 3 × CheW and 3 × CheY, but no CheZ). In this study, we found a fourth cheY and expressed these R. sphaeroides proteins in E. coli . CheA2 (but not CheA1) restored swarming to an E. coli cheA mutant (RP9535). CheW3 (but not CheW2) restored swarming to a cheW mutant of E. coli (RP4606). R. sphaeroides CheYs did not affect E. coli lacking CheY, but restored swarming to a cheZ strain (RP1616), indicating that they can act as signal terminators in E. coli . An E. coli CheY, which is phosphorylated but cannot bind the motor (CheY109KR), was expressed in RP1616 but had no effect. Overexpression of CheA2, CheW2, CheW3, CheY1, CheY3 and CheY4 inhibited chemotaxis of wild‐type E. coli (RP437) by increasing its smooth‐swimming bias. While some R. sphaeroides proteins restore tumbling to smooth‐swimming E. coli mutants, their activity is not controlled by the chemosensory receptors. R. sphaeroides possesses a phosphorelay cascade compatible with that of E. coli , but has additional incompatible homologues.