Di Gennaro Patrizia, Ferrara Silvia, Ronco Ilaria, Galli Enrica, Sello Guido, Papacchini Maddalena, Bestetti Giuseppina
Department of Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126, Milan, Italy.
Arch Microbiol. 2007 Aug;188(2):117-25. doi: 10.1007/s00203-007-0226-9. Epub 2007 Mar 22.
Pseudomonas fluorescens ST is a styrene degrading microorganism that, by the sequential oxidation of the vinyl side chain, converts styrene to phenylacetic acid. The cluster of styrene upper pathway catabolic genes (sty genes) has been previously localized on a chromosomal region. This report describes the isolation, sequencing and analysis of a new chromosomal fragment deriving from the ST strain genomic bank that contains the styrene lower degradative pathway genes (paa genes), involved in the metabolism of phenylacetic acid. Analysis of the paa gene cluster led to the description of 14 putative genes: a gene encoding a phenylacetyl-CoA ligase (paaF), the enzyme required for the activation of phenylacetic acid; five ORFs encoding the subunits of a ring hydroxylation multienzymatic system (paaGHIJK); the gene paaW encoding a membrane protein of unknown function; five genes for a beta-oxidation-like system (paaABCDE), involved in the steps following the aromatic ring cleavage; a gene encoding a putative permease (paaL) and a gene (paaN) probably involved in the aromatic ring cleavage. The function of some of the isolated genes has been proved by means of biotransformation experiments.
荧光假单胞菌ST是一种能降解苯乙烯的微生物，它通过乙烯基侧链的顺序氧化将苯乙烯转化为苯乙酸。苯乙烯上途径分解代谢基因簇（sty基因）先前已定位在一个染色体区域。本报告描述了从ST菌株基因组文库中分离、测序和分析一个新的染色体片段，该片段包含参与苯乙酸代谢的苯乙烯下分解代谢途径基因（paa基因）。对paa基因簇的分析确定了14个推定基因：一个编码苯乙酰辅酶A连接酶（paaF）的基因，该酶是激活苯乙酸所需的酶；五个编码环羟基化多酶系统亚基的开放阅读框（paaGHIJK）；编码功能未知膜蛋白的paaW基因；五个参与类β-氧化系统（paaABCDE）的基因，参与芳香环裂解后的步骤；一个编码推定通透酶的基因（paaL）和一个可能参与芳香环裂解的基因（paaN）。通过生物转化实验证明了一些分离基因的功能。
