Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
J Hazard Mater. 2013 Oct 15;261:246-52. doi: 10.1016/j.jhazmat.2013.07.019. Epub 2013 Jul 19.
Three 2,3-dihydroxybiphenyl 1,2-dioxygenase genes (designated as bphC1, bphC2 and bphC3) were cloned from a biphenyl-degrading strain Achromobacter sp. BP3. The amino acid sequence of BphC1 and BphC3 had high similarity (>99%) with the reported BphCs, while BphC2 showed relatively low identity (29.51-50.17%) with the reported BphCs, which indicated that bphC2 might be a novel gene. The bphC1, bphC2 and bphC3 genes were expressed in Escherichia coli BL21 and the products were homogenously purified. BphC1, BphC2 and BphC3 displayed maximum activity at 30°C, 30°C and 40°C, respectively. Their optimal catalysis pH was 8.0, 9.0 and 9.0, respectively. BphC1 and BphC2 had higher substrate affinity and catalytic efficiency on 2,3-dihydroxybiphenyl, while BphC3 exhibited these features on aromatic monocyclic substrates. The bphC1 gene was only induced by biphenyl and bphC3 was induced by both biphenyl and toluene, while bphC2 was constitutively expressed in strain BP3. These results suggested that BphC1 and BphC3 played a role in the upstream and downstream metabolic pathways of biphenyl, respectively. However, BphC2 might play a supplementary role and contribute more to the upstream than to the downstream pathway.
三个 2,3-二羟基联苯 1,2-双加氧酶基因（分别命名为 bphC1、bphC2 和 bphC3）从联苯降解菌株 Achromobacter sp. BP3 中克隆得到。BphC1 和 BphC3 的氨基酸序列与报道的 BphCs 具有高度相似性（>99%），而 BphC2 与报道的 BphCs 显示相对较低的同一性（29.51-50.17%），这表明 bphC2 可能是一个新基因。bphC1、bphC2 和 bphC3 基因在大肠杆菌 BL21 中表达，并进行了均匀纯化。BphC1、BphC2 和 BphC3 的最大活性分别在 30°C、30°C 和 40°C 下达到。它们的最佳催化 pH 值分别为 8.0、9.0 和 9.0。BphC1 和 BphC2 对 2,3-二羟基联苯具有更高的底物亲和力和催化效率，而 BphC3 对芳香单环底物则具有这些特征。bphC1 基因仅被联苯诱导，bphC3 被联苯和甲苯共同诱导，而 bphC2 在 BP3 菌株中组成型表达。这些结果表明，BphC1 和 BphC3 分别在联苯的上游和下游代谢途径中发挥作用。然而，BphC2 可能发挥补充作用，对上游途径的贡献大于下游途径。
