Biochemical and molecular characterization of the Bacillus subtilis acetoin catabolic pathway

• Published in: Journal of bacteriology Vol. 181; no. 12; pp. 3837 - 3841
• Main Authors: Huang, M, Oppermann-Sanio, F B, Steinbüchel, A
• Format: Journal Article
• Language: English
• Published: United States American Society for Microbiology 01.06.1999; American Society for Microbiology (ASM)
• Series: Note
• Subjects: Acetoin - metabolism; Acetoin Dehydrogenase - genetics; Acetoin Dehydrogenase - metabolism; Bacillus subtilis; Bacillus subtilis - genetics; Bacillus subtilis - metabolism; Bacteria; Bacteriology; Chromosomes, Bacterial; Clostridium magnum; Enzymes; Escherichia coli - genetics; Gene Library; Kinetics; Metabolism; Multigene Family; Mutation; Open Reading Frames; Physiology and Metabolism; Restriction Mapping
• ISSN: 0021-9193; 1098-5530
• DOI: 10.1128/jb.181.12.3837-3841.1999

A recent study indicated that Bacillus subtilis catabolizes acetoin by enzymes encoded by the acu gene cluster (F. J. Grundy, D. A. Waters, T. Y. Takova, and T. M. Henkin, Mol. Microbiol. 10:259-271, 1993) that are completely different from those in the multicomponent acetoin dehydrogenase enzyme system (AoDH ES) encoded by aco gene clusters found before in all other bacteria capable of utilizing acetoin as the sole carbon source for growth. By hybridization with a DNA probe covering acoA and acoB of the AoDH ES from Clostridium magnum, genomic fragments from B. subtilis harboring acoA, acoB, acoC, acoL, and acoR homologous genes were identified, and some of them were functionally expressed in E. coli. Furthermore, acoA was inactivated in B. subtilis by disruptive mutagenesis; these mutants were impaired to express PPi-dependent AoDH E1 activity to remove acetoin from the medium and to grow with acetoin as the carbon source. Therefore, acetoin is catabolized in B. subtilis by the same mechanism as all other bacteria investigated so far, leaving the function of the previously described acu genes obscure.