Yin Xihou, O'Hare Thomas, Gould Steven J, Zabriskie T Mark
Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331, USA.
Gene. 2003 Jul 17;312:215-24. doi: 10.1016/s0378-1119(03)00617-6.
The tuberactinomycins are a family of basic cyclic peptides that exhibit potent antitubercular activity. These peptides are characterized by the presence of an amino acid with a 6-membered cyclic guanidine side chain (capreomycidine) and two or more 2,3-diaminopropionate residues. Viomycin (tuberactinomycin B) is a well-studied member of the family, was once prescribed for the treatment of tuberculosis, and has been shown to block translocation during protein biosynthesis. The gene cluster encoding viomycin biosynthesis was identified and cloned from Streptomyces vinaceus. The cluster was identified by screening genomic libraries with the viomycin phosphotransferase self-resistance gene (vph) and non-ribosomal peptide synthetase (NRPS) gene probes amplified from S. vinaceus genomic DNA. The viomycin cluster was localized to ca. 120 kb of contiguous DNA defined by four overlapping cosmid inserts. Each cosmid hybridized with one or more peptide synthetase gene probes and two also hybridized with vph. Confirmation that the cluster encoded viomycin biosynthesis was obtained from the disruption of two NRPS adenylation domains. Partial sequence analysis revealed an ORF (svox) predicted to encode a rare non-heme iron, alpha-ketoglutarate dependent oxygenase proposed to function in the oxidative cyclization of arginine to the capreomycidine residue. Insertional disruption of svox resulted in complete loss of viomycin production, confirming its involvement in the pathway.
结核放线菌素是一类具有强大抗结核活性的碱性环肽家族。这些肽的特征在于存在带有六元环胍侧链的氨基酸（卷曲霉素）以及两个或更多个2,3-二氨基丙酸残基。紫霉素（结核放线菌素B）是该家族中一个经过充分研究的成员，曾被用于治疗结核病，并且已显示其在蛋白质生物合成过程中会阻断转位。编码紫霉素生物合成的基因簇是从酒红色链霉菌中鉴定并克隆出来的。该基因簇是通过用从酒红色链霉菌基因组DNA中扩增得到的紫霉素磷酸转移酶自身抗性基因（vph）和非核糖体肽合成酶（NRPS）基因探针筛选基因组文库来鉴定的。紫霉素基因簇定位于由四个重叠粘粒插入片段界定的约120 kb连续DNA区域。每个粘粒都与一个或多个肽合成酶基因探针杂交，并且有两个还与vph杂交。通过破坏两个NRPS腺苷化结构域证实了该基因簇编码紫霉素生物合成。部分序列分析揭示了一个开放阅读框（svox），预计其编码一种罕见的非血红素铁、α-酮戊二酸依赖性加氧酶，推测该酶在将精氨酸氧化环化为卷曲霉素残基的过程中发挥作用。svox的插入破坏导致紫霉素产量完全丧失，证实了其参与该途径。
