Characterization of a novel DNA glycosylase from S. sahachiroi involved in the reduction and repair of azinomycin B induced DNA damage.
Characterization of a novel DNA glycosylase from S. sahachiroi involved in the reduction and repair of azinomycin B induced DNA damage.
复制标题
一种来自 S. sahachiroi 的新型 DNA 糖基化酶的表征，该酶参与减少和修复阿齐霉素 B 诱导的 DNA 损伤
DOI：
10.1093/nar/gkv949
复制
发表时间：
2016-01-08
影响因子：
14.9
通讯作者：
He J
中科院分区：
文献类型：
--
作者：
Wang S;Liu K;Xiao L;Yang L;Li H;Zhang F;Lei L;Li S;Feng X;Li A;He J
Azinomycin B是一种杂合聚酮/非核糖体肽天然产物，通过与双链DNA共价结合并诱导链间交联而具有抗肿瘤活性。在azinomycin B的生物合成研究中，发现与azinomycin B基因簇相邻的基因（orf 1）对于生产者Streptomyces sahachiroi ATCC 33158的生存是必需的。序列分析显示，Orf 1属于保守细菌蛋白HTH_42超家族，广泛分布于致病菌和抗生素产生菌中，功能未知。当在azinomycin敏感菌株中异源表达时，该蛋白质表现出对azinomycin B的保护作用。EMSA分析表明其序列非特异性结合DNA和azinomycin B-加合位点的结构特异性结合，和ChIP分析揭示了广泛的协会Orf 1与染色质在体内。有趣的是，Orf 1不仅通过蛋白质-DNA相互作用保护靶位点，而且还能够修复azinomycin B介导的DNA交联。它具有DNA糖基化酶样活性，并通过去除交联中的两个加合的含氮碱基特异性地修复由azinomycin B诱导的DNA损伤。这种双功能蛋白质作为一种新型的DNA结合蛋白大量结合基因组DNA以降低药物攻击风险，并作为一种新型的DNA糖基化酶触发碱基切除修复系统。
Azinomycin B is a hybrid polyketide/nonribosomal peptide natural product and possesses antitumor activity by interacting covalently with duplex DNA and inducing interstrand crosslinks. In the biosynthetic study of azinomycin B, a gene (orf1) adjacent to the azinomycin B gene cluster was found to be essential for the survival of the producer, Streptomyces sahachiroi ATCC33158. Sequence analyses revealed that Orf1 belongs to the HTH_42 superfamily of conserved bacterial proteins which are widely distributed in pathogenic and antibiotic-producing bacteria with unknown functions. The protein exhibits a protective effect against azinomycin B when heterologously expressed in azinomycin-sensitive strains. EMSA assays showed its sequence nonspecific binding to DNA and structure-specific binding to azinomycin B-adducted sites, and ChIP assays revealed extensive association of Orf1 with chromatin in vivo. Interestingly, Orf1 not only protects target sites by protein–DNA interaction but is also capable of repairing azinomycin B-mediated DNA cross-linking. It possesses the DNA glycosylase-like activity and specifically repairs DNA damage induced by azinomycin B through removal of both adducted nitrogenous bases in the cross-link. This bifunctional protein massively binds to genomic DNA to reduce drug attack risk as a novel DNA binding protein and triggers the base excision repair system as a novel DNA glycosylase.