Fate of the SpoIIAB*-ADP Liberated after SpoIIAB Phosphorylates SpoIIAA of Bacillus subtilis
AUTOR(ES)
Lee, Chung-Sheng
FONTE
American Society for Microbiology
RESUMO
Phosphorylation of SpoIIAA catalyzed by SpoIIAB helps to regulate the first sporulation-specific ς factor, ςF, of Bacillus subtilis. The steady-state rate of phosphorylation is known to be exceptionally slow and to be limited by the return of the protein kinase, SpoIIAB, to a catalytically active state. Previous work from this laboratory has suggested that, after catalyzing the phosphorylation, SpoIIAB is in a form (SpoIIAB*) that does not readily release ADP. We now show that the rate of release of ADP from the SpoIIAB*-ADP complex was much diminished by the presence of unreacted SpoIIAA, suggesting that SpoIIAA can form a long-lived ternary complex with SpoIIAB*-ADP in which the SpoIIAB* form is stabilized. In kinetic studies of the phosphorylation of SpoIIAA, the ternary complex SpoIIAA-SpoIIAB*-ADP could be distinguished from the short-lived complex SpoIIAA-SpoIIAB-ADP, which can be readily produced in the absence of an enzymatic reaction.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=94765Documentos Relacionados
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