Gene cloning, purification, and characterization of 2,3-diaminopropionate ammonia-lyase from Escherichia coli.
2,3-Diaminopropionate ammonia-lyase (DAPAL), which catalyzes alpha,beta-elimination of 2,3-diaminopropionate regardless of its stereochemistry, was purified from Salmonella typhimurium. We cloned the Escherichia coli ygeX gene encoding a putative DAPAL and purified the gene product to homogeneity. The protein obtained contained pyridoxal 5'-phosphate and was composed of two identical subunits with a calculated molecular weight of 43,327. It catalyzed the alpha,beta-elimination of both D- and L-2,3-diaminopropionate. The results confirmed that ygeX encoded DAPAL. The enzyme acted on D-serine, but its catalytic efficiency was only 0.5% that with D-2,3-diaminopropionate. The enzymologic properties of E. coli DAPAL resembled those of Salmonella DAPAL, except that L-serine, D-and L-beta-Cl-alanine were inert as substrates of the enzyme from E. coli. DAPAL had significant sequence similarity with the catalytic domain of L-threonine dehydratase, which is a member of the fold-type II group of pyridoxal phosphate enzymes, together with D-serine dehydratase and mammalian serine racemase.
Uo
Takuma
T
Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan.
Yoshimura
Tohru
T
Nishiyama
Tozo
T
Esaki
Nobuyoshi
N
D000595:Amino Acid Sequence; D000642:Ammonia-Lyases / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology* / Q000235:genetics; D015870:Gene Expression; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015091:beta-Alanine / Q000031:analogs & derivatives* / Q000378:metabolism*
D015091:beta-Alanine; C011757:2,3-diaminopropionic acid; D000642:Ammonia-Lyases; C023147:diaminopropionate ammonia-lyase