科研之友
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摘要
Plasmid pMET7C containing a 6.05 kb DNA insert from Clostridium acetobutylicum P262 made Escherichia coli F19 cells sensitive to metronidazole. The nucleotide sequence of the C, acetobutylicum DNA controlling metronidazole sensitivity in E. coil 519 revealed an ORF of 972 bp which encoded a protein of 324 amino acids with a calculated M(r) of 35000. The amino acid sequence encoded by the ORF contained a helix-turn-helix DNA-binding domain and was homologous to the catabolite control protein, CcpA, from Bacillus subtilis and Bacillus megaterium, a tRNA repressor of E. coil encoded by the shl gene, and the GalR, Lacl and PurR repressors of E. coil. The C. acetobutylicum ORF, which was termed regA, complemented a B, subtilis ccpA mutant and an E. coil shl mutant, but was unable to complement E. coil galR, lacl or purR mutants. To determine whether the regA gene product was involved in the regulation of amylase gene expression in C. acetobutylicum, a starch-degrading enzyme gene (staA) from C. acetobutylicum NCIMB 8052 was cloned. The RegA protein inhibited the degradation of starch by the C. acetobutylicum staA gene product in E. coli.
- 出版日期1995-4
