Characterization of the AmyI protein involved in the catabolite repression of alpha-amylase synthesis in Bacillus subtilis = 고초균에서 아밀라제 생합성의 Catabolite Repression에 관여하는 Amyl 단백질의 특성에 관한 연구

Abstract

The amyO (amylase operator) region in B. suvtilis has 79% homology with lacO consensus sequence of E. coli, and 92% with galO consensus sequence of E coli. The AmyI(amyO binding protein) protein was purified as an amyO-binding protein specifically involved in the catabolite repression of a-amylase synthesis. Run-off transcription experiment indicated that the AmyI protein inhibited the initiation of the amyE transcription from amylase promoter in vitro. Binding studies of the AmyL protein demonstrated positive cooperativity with amyO, wild type operater, but non-cooperativity with amyOgra-10. The bingding of the AmyI protein to wild type amyO was less sensitive to salt concentration than that of the AmyL to amyOgra-10. This evidence suggests that the AmyL protein ba an amylase repressor protein to regulate amylase synthesis in vitro.