New Metabolites in Dibenzofuran Cometabolic Degradation by a Biphenyl-Cultivated Pseudomonas putida Strain B6-2
New Metabolites in Dibenzofuran Cometabolic Degradation by a Biphenyl-Cultivated Pseudomonas putida Strain B6-2
复制标题
联苯培养的恶臭假单胞菌 B6-2 菌株二苯并呋喃共代谢降解中的新代谢物
DOI：
10.1021/es901991d
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发表时间：
2009-11-15
影响因子：
11.4
通讯作者：
Xu, Ping
中科院分区：
文献类型：
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作者：
Li, Qinggang;Wang, Xiaoyu;Xu, Ping
从土壤中分离到一株联苯（BP）利用菌B6-2，经鉴定为恶臭假单胞菌（Pseudomonasputida）。BP培养的B6-2细胞能够通过侧向双氧合和间位裂解途径转化二苯并呋喃（DBF）。检测到环裂解产物2-羟基-4-（3 '-氧代-3' H-苯并呋喃-2 '-亚基）丁-2-烯酸（HOBB）为主要代谢产物。B6-2生长细胞也可以共代谢降解DBF使用BP作为主要底物。表达BP双加氧酶、BP-二氢二醇脱氢酶和二羟基联苯双加氧酶的重组大肠杆菌菌株DH 10 B（pUC 118 bphABC）被证明能够将DBF转化为HOBB。利用重组体产生的纯化HOBB作为B6-2的底物，我们新鉴定了一系列苯并呋喃衍生物作为代谢产物。这些代谢产物的结构表明菌株B6-2采用了一种未报道的HOBB降解途径。在该途径中，提出HOBB通过两个连续的双键氢化步骤转化为2-氧代-4-（3 '-氧代苯并呋喃-2'-基）丁酸和2-羟基-4-（3 '-氧代苯并呋喃-2'-基）丁酸（D4）。建议D4经历包括脱羧和氧化的反应以产生3-（3 '-氧代苯并呋喃-2'-基）丙酸（D 6）。3-羟基-3-（3 '-氧代苯并呋喃-2'-基）丙酸（D 7）和2-（3 '-氧代苯并呋喃-2'-基）乙酸（D8）分别代表参与D 6 β-和α-氧化过程的代谢物。建议D 7和D8转化为它们各自的产物3-羟基-2，3-二氢苯并呋喃-2-羧酸（D10）和2-（3 ′-羟基-2 ′，3 ′-二氢苯并呋喃-2 ′-基）乙酸。建议D10通过2，3-二氢-2，3-二羟基苯并呋喃、2-氧代-2-（2 '-羟基苯基）乙酸和2-羟基-2-（2'-羟基苯基）乙酸转化为水杨酸（D14）。进一步的实验结果表明，B6-2能够以D14为唯一碳源生长。由于苯并呋喃衍生物可能具有生物学、药理学和毒性特性，因此从生物技术和环境角度阐明这一途径具有重要意义。
A biphenyl (BP)-utilizing bacterium, designated B6-2, was isolated from soil and identified as Pseudomonas putida. BP-grown B6-2 cells were capable of transforming dibenzofuran (DBF) via a lateral dioxygenation and meta-cleavage pathway. The ring cleavage product 2-hydroxy-4-(3'-oxo-3'H-benzofuran-2'-yliden)but-2-enoic acid (HOBB) was detected as a major metabolite. B6-2 growing cells could also cometabolically degrade DBF using BP as a primary substrate. A recombinant Escherichia coli strain DH10B (pUC118bphABC) expressing BP dioxygenase, BP-dihydrodiol dehydrogenase, and dihydroxybiphenyl dioxygenase was shown to be capable of transforming DBF to HOBB. Using purified HOBB that was produced by the recombinant as the substrate for B6-2, we newly identified a series of benzofuran derivatives as metabolites. The structures of these metabolites indicate that an unreported HOBB degradation pathway is employed by strain B6-2. In this pathway, HOBB is proposed to be transformed to 2-oxo-4-(3'-oxobenzofuran-2'-yl)butanoic acid and 2-hydroxy-4-(3'-oxobenzofuran-2'-yl)butanoic acid (D4) through two sequential double-bond hydrogenation steps. D4 is suggested to undergo reactions including decarboxylation and oxidation to produce 3-(3'-oxobenzofuran-2'-yl)propanoic acid (D6). 3-Hydroxy-3-(3'-oxobenzofuran-2'-yl)propanoic acid (D7) and 2-(3'-oxobenzofuran-2'-yl)acetic acid (D8) would represent metabolites involved in the processes of beta- and alpha-oxidation of D6, respectively. D7 and D8 are suggested to be transformed to their respective products 3-hydroxy-2,3-dihydrobenzofuran-2-carboxylic acid (D10) and 2-(3'-hydroxy-2',3'-dihydrobenzofuran-2'-yl)acetic acid. D10 is proposed to be transformed to salicylic acid (D14) via 2,3-dihydro-2,3-dihydroxybenzofuran, 2-oxo-2-(2'-hydroxyphenyl)acetic acid and 2-hydroxy-2-(2'-hydroxyphenyl)acetic acid. Further experimental results revealed that B6-2 was capable of growing with D14 as the sole carbon source. Because benzofuran derivatives may have biological, pharmacological, and toxic properties, the elucidation of this now pathway should be significant from both biotechnological and environmental views.