Deciphering the biosynthesis pathway of the antitumor thiocoraline from a marine actinomycete and its expression in two Streptomyces species
Deciphering the biosynthesis pathway of the antitumor thiocoraline from a marine actinomycete and its expression in two Streptomyces species
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DOI：
10.1002/cbic.200500325
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发表时间：
2006-02-01
期刊：
影响因子：
3.2
通讯作者：
Salas, JA
中科院分区：
文献类型：
--
作者：
Lombó, F;Velasco, A;Salas, JA
硫代珊瑚碱是一种硫代沉积肽抗肿瘤化合物，由两种放线菌Micromonospora sp. ACM2-092和Micromonospora sp. ML1产生，分离自莫桑比克印度洋沿岸发现的两种海洋无脊椎动物（软珊瑚和软体动物）。利用非核糖体肽合成酶（NRPS）一致序列的低聚物，从小单孢菌ML1染色体上扩增出6个含有NRPS腺苷化结构域的PCR片段。每个腺苷化结构域的插入失活表明其中两个产生不产生突变体，从而表明这些结构域参与硫代珊瑚碱的生物合成。对64.6 kbp DNA区域进行测序，发现存在36个完整的开放阅读框（orf）和2个不完整的开放阅读框（orf）。在白色链霉菌和S. lividans中，含有26个orf的约53 kbp区域的异源表达导致这些链霉菌产生硫代珊瑚碱。令人惊讶的是，鉴定出的基因簇比基于硫代珊瑚碱氨基酸数量的预期含有更多的NRPS模块。根据各自模块的共线性，TioR和TioS很可能构成参与硫代珊瑚碱主链生物合成的NRPS。另外两个NRPSs TioY和TioZ可能负责小肽分子的生物合成，该小肽分子可能参与调节小单孢菌ML1中噻可林的生物合成。此外，还提出了一种不同寻常的起始单位- 3-羟基喹啉酸的生物合成途径。
Thiocoraline is a thiodepsipeptide antitumor compound produced by two actinomycetes Micromonospora sp. ACM2-092 and Micromonospora sp. ML1, isolated from two marine invertebrates (a soft coral and a mollusc) found of the Indian Ocean coast of Mozambique. By using oligoprimers derived from nonribosomal peptide synthetase (NRPS) consensus sequences, six PCR fragments containing putative NRPS adenylation domains were amplified from the chromosome of Micromonospora sp. ML1. Insertional inactivation of each adenylation domain showed that two of them generated nonproducing mutants, thereby indicating that these domains were involved in thiocoraline biosynthesis. Sequencing of a 64.6 kbp DNA region revealed the presence of 36 complete open reading frames (ORFs) and two incomplete ones. Heterologous expression of a region of about 53 kbp, containing 26 of the ORFs, in Streptomyces albus and S. lividans led to the production of thiocoraline in these streptomycetes. Surprisingly, the identified gene cluster contains more NRPS modules than expected on the basis of the number of amino acids of thiocoraline. TioR and TioS would most probably constitute the NRPS involved in the biosynthesis of the thiocoraline backbone, according to the colinearity of the respective modules. It is proposed that two other NRPSs, TioY and TioZ could be responsible for the biosynthesis of a small peptide molecule which could be involved in regulation of the biosynthesis of thicoraline in Micromonospora sp. ML1. In addition, a pathway is proposed for the biosynthesis of the unusual starter unit, 3-hydroxy-quinaldic acid.