Takenaka S, Murakami S, Kim Y J, Aoki K
Department of Biofunctional Chemistry, Faculty of Agriculture, Graduate School of Science and Technology, Kobe University, Rokko, Japan.
Arch Microbiol. 2000 Oct;174(4):265-72. doi: 10.1007/s002030000203.
A 13.9-kb region, which contained the 2-aminophenol 1,6-dioxygenase genes (amnBA) reported before, was cloned from the 2-aminophenol-assimilating bacterium Pseudomonas sp. AP-3. The complete nucleotide sequence of this region was determined and six genes were found downstream of amnBA. The eight genes together were designated amnBACFEDHG. Each gene was similar to the corresponding gene operating in the meta-cleavage pathway, except for amnB, amnA, and amnD. The four 2-aminophenol-metabolizing enzymes, 2-aminomuconic 6-semialdehyde dehydrogenase, 2-aminomuconate deaminase, 4-oxalocrotonate decarboxylase, and 2-oxopent-4-enoate hydratase, were purified and characterized. NH2-terminal amino acid sequences of each purified enzyme agreed with those deduced from amnC, amnF, amnE, and amnD, respectively. These genes were therefore assigned as the genes encoding these respective proteins. The tight clustering of the amn genes, which were all transcribed in the same direction, raised the possibility that these genes formed a single operon. The organization of the amn genes was entirely different from that of the atd, dmp, and xyl genes reported in the meta-cleavage pathway, although these latter genes clustered similarly.
从能同化2-氨基酚的假单胞菌属AP-3菌株中克隆出一个13.9 kb的区域，该区域包含之前报道的2-氨基酚1,6 -双加氧酶基因（amnBA）。测定了该区域的完整核苷酸序列，在amnBA下游发现了6个基因。这8个基因合称为amnBACFEDHG。除了amnB、amnA和amnD外，每个基因都与间位裂解途径中起作用的相应基因相似。对4种2-氨基酚代谢酶，即2-氨基粘康酸6-半醛脱氢酶、2-氨基粘康酸脱氨酶、4-草酰巴豆酸脱羧酶和2-氧代戊-4-烯酸水合酶进行了纯化和特性鉴定。每种纯化酶的NH2末端氨基酸序列分别与从amnC、amnF、amnE和amnD推导的序列一致。因此，这些基因被确定为编码这些相应蛋白质的基因。amn基因紧密成簇，且均按相同方向转录，这增加了这些基因形成单个操纵子的可能性。amn基因的组织形式与间位裂解途径中报道的atd、dmp和xyl基因完全不同，尽管后几种基因也类似地成簇。
