Biochemical study of multiple CheY response regulators of the chemotactic pathway of Rhodobacter sphaeroides.
The six copies of the response regulator CheY from Rhodobacter sphaeroides bind to the switch protein FliM. Phosphorylation by acetyl phosphate (AcP) was detected by tryptophan fluorescence quenching in three of the four CheYs that contain this residue. Autophosphorylation with Ac(32)P was observed in five CheY proteins. We also show that all of the cheY genes are expressed simultaneously; therefore, in vivo all of the CheY proteins could bind to FliM to control the chemotactic response. Consequently, we hypothesize that in this complex chemotactic system, the binding of some CheY proteins to FliM, does not necessarily imply switching of the flagellar motor.
Ferré
Axelle
A
Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, AP Postal 70-243, 04510 Mexico DF, Mexico.
De La Mora
Javier
J
Ballado
Teresa
T
Camarena
Laura
L
Dreyfus
Georges
G
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002633:Chemotaxis / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D000072236:Methyl-Accepting Chemotaxis Proteins; D008969:Molecular Sequence Data; D010766:Phosphorylation; D012242:Rhodobacter sphaeroides / Q000254:growth & development / Q000378:metabolism*
D001426:Bacterial Proteins; D008565:Membrane Proteins; D000072236:Methyl-Accepting Chemotaxis Proteins; C066821:FliM protein, Bacteria