A NEW NYLON OLIGOMER DEGRADATION GENE (NYLC) ON PLASMID POAD2 FROM A FLAVOBACTERIUM SP
A NEW NYLON OLIGOMER DEGRADATION GENE (NYLC) ON PLASMID POAD2 FROM A FLAVOBACTERIUM SP
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DOI：
10.1128/jb.174.24.7948-7953.1992
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发表时间：
1992-12-01
影响因子：
3.2
通讯作者：
OKADA, H
中科院分区：
文献类型：
--
作者：
NEGORO, S;KAKUDO, S;OKADA, H
黄杆菌属菌株KI 725携带质粒pOAD 21，其是尼龙寡聚体降解质粒pOAD 2的衍生物，其中所有nylA（6-氨基己酸环状二聚体水解酶[EI]的基因）缺失，但保留nylB（6-氨基己酸二聚体水解酶[EII]的基因）。KI 725在从尼龙工厂获得的未分级尼龙低聚物（Noml）上没有显示出生长，所述未分级尼龙低聚物（Noml）作为唯一碳源和氮源（Noml最小平板）。KI 725细胞的提取物具有对Noml的水解活性（约为KI 72活性的5%），但pOAD 2-治愈的菌株（KI 722和KI 723）没有显示出活性。在Noml最小平板上生长的KI 725 R菌株以10（-7）/细胞的频率从KI 725中自发分离。在KI 725 R菌株中对Noml的活性增强（KI 72活性的10至30%）。这种新的Noml降解酶（EIII，nylC基因产物）不仅水解Noml，而且水解N-苄氧羰基-6-氨基己酸三聚体，其是不被EI或EII水解的底物。克隆和序列分析表明，nylC基因位于pOAD 21上nylB附近，是一个1,065-bp的开放阅读框架，对应于355个氨基酸残基。nylC基因的核苷酸序列和推导的EIII的氨基酸序列与nylA（EI）和nylB（EII）的序列没有可检测到的同源性。
Flavobacterium sp. strain KI725 harbors plasmid pOAD21, a derivative of nylon oligomer-degradative plasmid pOAD2, in which all of nylA (the gene for 6-aminohexanoate cyclic dimer hydrolase [EI]) was deleted but nylB (the gene for 6-aminohexanoate dimer hydrolase [EII]) was retained. KI725 showed no growth on unfractionated nylon oligomers (Nom1) obtained from a nylon factory as a sole carbon and nitrogen source (Noml minimum plate). Extracts of KI725 cells possessed hydrolytic activity for Noml (approximately 5% of the activity of KI72), but pOAD2-cured strains (KI722 and KI723) showed no activity. KI725R strains which grew on the Noml minimum plate were spontaneously isolated from KI725 at a frequency of 10(-7) per cell. Activity toward Noml was enhanced in KI725R strains (10 to 30% of the activity of KI72). This new Noml degrading enzyme (EIII, the nylC gene product) hydrolyzed not only Noml but also the N-carbobenzoxy-6-aminohexanoate trimer, a substrate which was not hydrolyzed by either EI or EII. Cloning and sequence analysis showed that the nylC gene is located close to nylB on pOAD21 and is a 1,065-bp open reading frame corresponding to 355 amino acid residues. The nucleotide sequence of the nylC gene and the deduced amino acid sequence of EIII had no detectable homology with the sequences of nylA (EI) and nylB (EII).