The genes coding for the conversion of carbazole to catechol are flanked by IS6100 elements in Sphingomonas sp. strain XLDN2-5.
The genes coding for the conversion of carbazole to catechol are flanked by IS6100 elements in Sphingomonas sp. strain XLDN2-5.
复制标题
鞘氨醇单胞菌中编码咔唑转化为儿茶酚的基因两侧为 IS6100 元件。
DOI：
10.1371/journal.pone.0010018
复制
发表时间：
2010-04-02
期刊：
影响因子：
3.7
通讯作者：
Xu P
中科院分区：
文献类型：
--
作者：
Gai Z;Wang X;Liu X;Tai C;Tang H;He X;Wu G;Deng Z;Xu P
咔唑是一种具有二恶英样结构的非柠檬酸类化合物，具有致突变和毒性活性。细菌通过募集外源基因来建立降解外源物质的途径，这是它们适应和生存所必需的。通常，这一过程由移动的遗传元件如质粒、转座子和插入序列介导。从咔唑降解鞘氨醇单胞菌菌株XLDN 2 -5中克隆了负责通过邻氨基苯甲酸酯将咔唑降解为邻苯二酚的酶的编码基因，并对其进行了测序和表征。car基因簇（carRAaBaBbCAc）和fdr基因在两侧伴随有两个拷贝的IS 6100元件，并且组织为IS 6100：：ISSsp 1-ORF 1-carRAaBaBbCAc-ORF 8-IS 6100-fdr-IS 6100。咔唑通过咔唑1，9 α-双加氧酶（CARDO，CarAaAcFdr）、间位裂解酶（CarBaBb）和水解酶（CarC）转化为邻氨基苯甲酸和2-羟基戊-2，4-二烯酸。fdr基因编码一种新的铁氧还蛋白还原酶，其缺失导致CarAa和CarAc对咔唑的转化活性降低。参与邻氨基苯甲酸转化为邻苯二酚的ant基因簇（antRAcAdAbAa）也夹在两个IS 6100元件之间，即IS 6100-antRAcAdAbAa-IS 6100。邻氨基苯甲酸1，2-双加氧酶（ANTDO）是由还原酶（AntAa）、铁氧还蛋白（AntAb）和双亚基末端加氧酶（AntAcAd）组成。反转录PCR结果表明，咔唑诱导XLDN 2 -5产生了carAaBaBbCAc基因簇、fdr基因簇和antRAcAdAbAa基因簇。在大肠杆菌中表达CARDO和ANTDO需要天然还原酶的存在以获得完全的酶活性。我们预测IS 6100可能在咔唑降解途径的建立中发挥重要作用，从而赋予宿主对环境中新化合物的适应能力。XLDN 2 -5株中的car和ant基因的组织是独特的，其显示了由IS 6100介导的基因募集的强烈进化踪迹，并且呈现了重排和途径建立的显著实例。
Carbazole is a recalcitrant compound with a dioxin-like structure and possesses mutagenic and toxic activities. Bacteria respond to a xenobiotic by recruiting exogenous genes to establish a pathway to degrade the xenobiotic, which is necessary for their adaptation and survival. Usually, this process is mediated by mobile genetic elements such as plasmids, transposons, and insertion sequences. The genes encoding the enzymes responsible for the degradation of carbazole to catechol via anthranilate were cloned, sequenced, and characterized from a carbazole-degrading Sphingomonas sp. strain XLDN2-5. The car gene cluster (carRAaBaBbCAc) and fdr gene were accompanied on both sides by two copies of IS6100 elements, and organized as IS6100::ISSsp1-ORF1-carRAaBaBbCAc-ORF8-IS6100-fdr-IS6100. Carbazole was converted by carbazole 1,9a-dioxygenase (CARDO, CarAaAcFdr), meta-cleavage enzyme (CarBaBb), and hydrolase (CarC) to anthranilate and 2-hydroxypenta-2,4-dienoate. The fdr gene encoded a novel ferredoxin reductase whose absence resulted in lower transformation activity of carbazole by CarAa and CarAc. The ant gene cluster (antRAcAdAbAa) which was involved in the conversion of anthranilate to catechol was also sandwiched between two IS6100 elements as IS6100-antRAcAdAbAa-IS6100. Anthranilate 1,2-dioxygenase (ANTDO) was composed of a reductase (AntAa), a ferredoxin (AntAb), and a two-subunit terminal oxygenase (AntAcAd). Reverse transcription-PCR results suggested that carAaBaBbCAc gene cluster, fdr, and antRAcAdAbAa gene cluster were induced when strain XLDN2-5 was exposed to carbazole. Expression of both CARDO and ANTDO in Escherichia coli required the presence of the natural reductases for full enzymatic activity. We predict that IS6100 might play an important role in the establishment of carbazole-degrading pathway, which endows the host to adapt to novel compounds in the environment. The organization of the car and ant genes in strain XLDN2-5 was unique, which showed strong evolutionary trail of gene recruitment mediated by IS6100 and presented a remarkable example of rearrangements and pathway establishments.
登录
查看更多内容
新分离的咔唑降解鞘氨醇单胞菌菌株对二苯并呋喃和二苯并噻吩的共代谢降解
影响因子：
4.4
作者：
Gai, Zhonghui;Yu, Bo;Xu, Ping
通讯作者：
Xu, Ping
DOI：
10.1016/s0006-291x(02)02183-6
发表时间：
2002-09-20
影响因子：
3.1
作者：
Kilbane, JJ;Daram, A;Kayser, KJ
通讯作者：
Kayser, KJ
影响因子：
14.9
作者：
Chenna, R;Sugawara, H;Thompson, JD
通讯作者：
Thompson, JD
影响因子：
64.8
作者：
MARTIN, C;TIMM, J;GICQUEL, B
通讯作者：
GICQUEL, B
影响因子：
3.2
作者：
Cai, M;Xun, LY
通讯作者：
Xun, LY