Multiple alkane hydroxylase systems in a marine alkane degrader, Alcanivorax dieselolei B-5.
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 (pGEc47ΔB) or P. fluorescens KOB2Δ1 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.
Key Lab of Marine Biogenetic Resources, Third Institute of Oceanography, State Oceanic Administration, China.
Chenli
C
Liu
Wanpeng
W
Wang
Yehui
Y
Wu
Zhongwen
Z
Zhou
Qiliang
Q
Lai
Zongze
Z
Shao
D053521:Alcanivoraceae / Q000201:enzymology* / Q000235:genetics; D000473:Alkanes / Q000378:metabolism*; D003001:Cloning, Molecular; D042926:Cytochrome P-450 CYP4A / Q000235:genetics / Q000378:metabolism*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D010084:Oxidation-Reduction; D011551:Pseudomonas fluorescens / Q000235:genetics / Q000378:metabolism; D016958:Pseudomonas putida / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity
D000473:Alkanes; D003577:Cytochrome P-450 Enzyme System; D042926:Cytochrome P-450 CYP4A