Cloning, sequencing, and expression of the genes encoding the adenosylcobalamin-dependent ethanolamine ammonia-lyase of Salmonella typhimurium.
Ethanolamine ammonia-lyase is a bacterial enzyme that catalyzes the adenosylcobalamin-dependent conversion of certain vicinal amino alcohols to oxo compounds and ammonia. Studies of ethanolamine ammonia-lyase from Clostridium sp. and Escherichia coli have suggested that the enzyme is a heterodimer composed of subunits of Mr approximately 55,000 and 35,000. Using a partial Sau3A Salmonella typhimurium library ligated into pBR328 and selecting by complementation of a mutant lacking ethanolamine ammonia-lyase activity, we have cloned the genes for the 2 subunits of the S. typhimurium enzyme. The genes were localized to a 6.5-kilobase fragment of S. typhimurium DNA, from which they could be expressed in E. coli under noninducing conditions. Sequencing of a 2526-base pair portion of this 6.5-kilobase DNA fragment revealed two open reading frames separated by 21 base pairs. The open reading frames encoded proteins of 452 and 286 residues whose derived N-terminal sequences were identical to the N-terminal sequences of the 2 subunits of the E. coli ethanolamine ammonia-lyase, except that residue 16 of the large subunit was asparagine in the E. coli sequence and aspartic acid in the S. typhimurium sequence.
Department of Molecular and Experimental Medicine, Research Institute of Scripps Clinic, La Jolla, California 92037.
L R
LR
Faust
J A
JA
Connor
D M
DM
Roof
J A
JA
Hoch
B M
BM
Babior
D000595:Amino Acid Sequence; D000642:Ammonia-Lyases / Q000235:genetics*; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004981:Ethanolamine Ammonia-Lyase / Q000235:genetics*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D012486:Salmonella typhimurium / Q000201:enzymology* / Q000235:genetics; D014158:Transcription, Genetic; D014805:Vitamin B 12 / Q000378:metabolism
D004269:DNA, Bacterial; D012333:RNA, Messenger; D000642:Ammonia-Lyases; D004981:Ethanolamine Ammonia-Lyase; D014805:Vitamin B 12