Yamamoto S, Mutoh N, Tsuzuki D, Ikai H, Nakao H, Shinoda S, Narimatsu S, Miyoshi S I
Faculty of Pharmaceutical Sciences, Okayama University, Japan.
Biol Pharm Bull. 2000 May;23(5):649-53. doi: 10.1248/bpb.23.649.
L-2,4-diaminobutyrate decarboxylase (DABA DC) catalyzes the formation of 1,3-diaminopropane (DAP) from DABA. In the present study, the ddc gene encoding DABA DC from Enterobacter aerogenes ATCC 13048 was cloned and characterized. Determination of the nucleotide sequence revealed an open reading frame of 1470 bp encoding a 53659-Da protein of 490 amino acids, whose deduced NH2-terminal sequence was identical to that of purified DABA DC from E. aerogenes. The deduced amino acid sequence was highly similar to those of Acinetobacter baumannii and Haemophilus influenzae DABA DCs encoded by the ddc genes. The lysine-307 of the E. aerogenes DABA DC was identified as the pyridoxal 5'-phosphate binding residue by site-directed mutagenesis. Furthermore, PCR analysis revealed the distribution of E. aerogenes ddc homologs in some other species of Enterobacteriaceae. Such a relatively wide occurrence of the ddc homologs implies biological significance of DABA DC and its product DAP.
L-2,4-二氨基丁酸脱羧酶（DABA DC）催化由DABA形成1,3-二氨基丙烷（DAP）。在本研究中，克隆并鉴定了产气肠杆菌ATCC 13048中编码DABA DC的ddc基因。核苷酸序列测定揭示了一个1470 bp的开放阅读框，编码一个由490个氨基酸组成的53659 Da蛋白质，其推导的NH2末端序列与产气肠杆菌纯化的DABA DC相同。推导的氨基酸序列与鲍曼不动杆菌和流感嗜血杆菌ddc基因编码的DABA DC高度相似。通过定点诱变确定产气肠杆菌DABA DC的赖氨酸-307为磷酸吡哆醛结合残基。此外，PCR分析揭示了产气肠杆菌ddc同源物在肠杆菌科其他一些物种中的分布。ddc同源物如此相对广泛的存在意味着DABA DC及其产物DAP具有生物学意义。
