ISOLATION AND IN-VITRO PHOSPHORYLATION OF SENSORY TRANSDUCTION COMPONENTS CONTROLLING ANAEROBIC INDUCTION OF LIGHT-HARVESTING AND REACTION-CENTER GENE-EXPRESSION IN RHODOBACTER-CAPSULATUS
K. Inoue et al., ISOLATION AND IN-VITRO PHOSPHORYLATION OF SENSORY TRANSDUCTION COMPONENTS CONTROLLING ANAEROBIC INDUCTION OF LIGHT-HARVESTING AND REACTION-CENTER GENE-EXPRESSION IN RHODOBACTER-CAPSULATUS, Biochemistry, 34(2), 1995, pp. 391-396
Anaerobic induction of light harvesting and reaction center gene expre
ssion involves two transacting factors termed RegA and RegB. Sequence
and mutational analysis has indicated that RegA and RegB constitute co
gnate components of a prokaryotic sensory transduction cascade with Re
gB comprising a membrane-spanning sensor kinase and RegA a cytosolic r
esponse regulator. In this study we have purified RegA, as well as a t
runcated portion of RegB (RegB') and undertaken an in vitro analysis o
f autophosphorylation and phosphotransfer activities. Incubation of Re
gB' with [gamma-P-32]ATP and MgCl2 resulted in phosphorylation of RegB
' (RegB'similar to P) over a 20-min incubation period. Incubation of R
egB'similar to P with RegA resulted in rapid transfer of the phosphate
from RegB' to RegA. In analogy to other characterized prokaryotic sen
sory transduction components, mutational and chemical stability studie
s also indicate that RegB' is autophosphorylated at a conserved histid
ine and that RegA accepts the phosphate from RegB at a conserved aspar
tate.