Multiple alkane hydroxylase systems in a marine alkane degrader, Alcanivorax dieselolei B-5
Multiple alkane hydroxylase systems in a marine alkane degrader, Alcanivorax dieselolei B-5
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DOI：
10.1111/j.1462-2920.2010.02416.x
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发表时间：
2011-05-01
影响因子：
5.1
通讯作者：
Shao, Zongze
中科院分区：
文献类型：
--
作者：
Liu, Chenli;Wang, Wanpeng;Shao, Zongze
柴油链球菌B-5菌株是一株能利用多种正构烷烃(C-5-C-36)作为唯一碳源的海洋细菌。然而，造成这一特点的机制仍有待建立。在这里，我们报道了来自南方红曲霉的四个烷烃羟基酶的性质，包括两个AlkB的同源物(AlkB1和AlkB2)，一个CYP153同源物(P450)，以及一个类似alma的烷烃羟基酶(Alma)。在恶臭假单胞菌GPo12(PGEc47 Delta B)或荧光假单胞菌KOB2 Delta 1中异源表达的alkB1、alkB2、P450和alma证实了它们在烷烃氧化中的作用。实时定量RT-PCR分析表明，这些基因可以被C-8到C-36的烷烃诱导。值得注意的是，P450和alma基因的表达仅在中链(C-8-C-16)或长链(C-22-C-36)正构烷烃存在时上调；而alkB1和alkB2对中链和长链正构烷烃(C-12-C-26)都有反应。此外，支链烷烃(伯克斯坦烷和植烷)显著提高了alkB1和alma的表达水平。我们的发现表明，多个烷烃羟基酶系统确保了对广泛链长范围的底物的利用。
P>Alcanivorax dieselolei strain B-5 is a marine bacterium that can utilize a broad range of n-alkanes (C-5-C-36) as sole carbon source. However, the mechanisms responsible for this trait remain to be established. Here we report on the characterization of four alkane hydroxylases from A. dieselolei, including two homologues of AlkB (AlkB1 and AlkB2), a CYP153 homologue (P450), as well as an AlmA-like (AlmA) alkane hydroxylase. Heterologous expression of alkB1, alkB2, p450 and almA in Pseudomonas putida GPo12 (pGEc47 Delta B) or P. fluorescens KOB2 Delta 1 verified their functions in alkane oxidation. Quantitative real-time RT-PCR analysis showed that these genes could be induced by alkanes ranging from C-8 to C-36. Notably, the expression of the p450 and almA genes was only upregulated in the presence of medium-chain (C-8-C-16) or long-chain (C-22-C-36) n-alkanes, respectively; while alkB1 and alkB2 responded to both medium- and long-chain n-alkanes (C-12-C-26). Moreover, branched alkanes (pristane and phytane) significantly elevated alkB1 and almA expression levels. Our findings demonstrate that the multiple alkane hydroxylase systems ensure the utilization of substrates of a broad chain length range.