Molecular characterization and analysis of the biosynthetic gene cluster for the azoxy antibiotic valanimycin
Molecular characterization and analysis of the biosynthetic gene cluster for the azoxy antibiotic valanimycin
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DOI：
10.1046/j.1365-2958.2002.03169.x
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发表时间：
2002-10-01
影响因子：
3.6
通讯作者：
Parry, RJ
中科院分区：
文献类型：
--
作者：
Garg, RP;Ma, YQ;Parry, RJ
绿色链霉菌MG456-HF10产生抗生素万乃尼霉素，这是一种自然产生的偶氮化合物。已知的万乃尼霉素是由缬氨酸和丝氨酸衍生而来，中间是异丁胺和异丁基羟胺，但对导致偶氮基形成的途径的各个阶段知之甚少。在以前的研究中，分离出了一种含有绿色链球菌DNA的粘粒，该粘粒可以使变铅青链霉菌TK24产生万乃尼霉素。从产万乃尼霉素的粘粒中亚克隆DNA，已经鉴定出一段22kb的DNA，足以在变铅青链霉菌TK24中生产万乃尼霉素。对这段DNA和周围的DNA进行测序，发现存在20个基因。基因破坏实验确定了valantiycin基因簇的边界，该基因簇似乎包含14个基因。该簇包括一个氨基酸脱羧酶基因(VlmD)、一个万乃尼霉素抗性基因(VlmF)、至少两个调控基因(vlmE、vlmI)、两个编码黄素单加氧酶的基因(vlmH、vlmR)、一个丝氨酸tRNA合成酶基因(VlmL)和7个功能未知的基因。VlmD的过量生产和表征表明，它催化L-缬氨酸的脱羧基。万乃馨基因簇的一个不同寻常的特征是，在其5‘端附近有四个参与支链氨基酸生物合成的基因。
Streptomyces viridifaciens MG456-hF10 produces the antibiotic valanimycin, a naturally occurring azoxy compound. Valanimycin is known to be derived from valine and serine with the intermediacy of isobutylamine and isobutylhydroxylamine, but little is known about the stages in the pathway leading to the formation of the azoxy group. In previous studies, a cosmid containing S. viridifaciens DNA was isolated that conferred valanimycin production upon Streptomyces lividans TK24. Subcloning of DNA from the valanimycin-producing cosmid has led to the identification of a 22 kb segment of DNA sufficient to allow valanimycin production in S. lividans TK24. Sequencing of this DNA segment and the surrounding DNA revealed the presence of 20 genes. Gene disruption experiments defined the boundaries of the valanimycin gene cluster, which appears to contain 14 genes. The cluster includes an amino acid decarboxylase gene (vlmD), a valanimycin resistance gene (vlmF), at least two regulatory genes (vlmE, vlmI), two genes encoding a flavin monooxygenase (vlmH, vlmR), a seryl tRNA synthetase gene (vlmL) and seven genes of unknown function. Overproduction and characterization of VlmD demonstrated that it catalyses the decarboxylation of L-valine. An unusual feature of the valanimycin gene cluster is that four genes involved in branched amino acid biosynthesis are located near its 5' end.