National Children's Research Centre, Our Lady's Children's Hospital Crumlin, Dublin, Ireland.
PLoS One. 2013 Sep 26;8(9):e75534. doi: 10.1371/journal.pone.0075534. eCollection 2013.
Cytochrome P450s are b-heme-containing enzymes that are able to introduce oxygen atoms into a wide variety of organic substrates. They are extremely widespread in nature having diverse functions at both biochemical and physiological level. The genome of C. jejuni 81-176 encodes a single cytochrome P450 (Cj1411c) that has no close homologues. Cj1411c is unusual in its genomic location within a cluster involved in the biosynthesis of outer surface structures. Here we show that E. coli expressed and affinity-purified C. jejuni cytochrome P450 is lipophilic, containing one equivalent Cys-ligated heme. Immunoblotting confirmed the association of cytochrome P450 with membrane fractions. A Cj1411c deletion mutant had significantly reduced ability to infect human cells and was less able to survive following exposure to human serum when compared to the wild type strain. Phenotypically following staining with Alcian blue, we show that a Cj1411c deletion mutant produces significantly less capsular polysaccharide. This study describes the first known membrane-bound bacterial cytochrome P450 and its involvement in Campylobacter virulence.
细胞色素 P450 是一种 b-血红素酶，能够将氧原子引入各种有机底物中。它们在自然界中广泛存在，具有生物化学和生理水平的多种功能。空肠弯曲菌 81-176 的基因组编码一种单一的细胞色素 P450（Cj1411c），没有密切的同源物。Cj1411c 在其基因组位置上是不寻常的，它位于参与外表面结构生物合成的簇内。在这里，我们表明，在大肠杆菌中表达和亲和纯化的空肠弯曲菌细胞色素 P450 是亲脂性的，含有一个当量的 Cys 连接的血红素。免疫印迹证实了细胞色素 P450 与膜部分的关联。与野生型菌株相比，Cj1411c 缺失突变体感染人细胞的能力显著降低，并且在暴露于人血清后存活能力降低。在用阿利辛蓝染色后表型上，我们表明 Cj1411c 缺失突变体产生的荚膜多糖明显减少。本研究描述了第一个已知的膜结合细菌细胞色素 P450 及其在弯曲杆菌毒力中的作用。
