A Four-Enzyme Pathway for 3,5-Dihydroxy-4-methylanthranilic Acid Formation and Incorporation into the Antitumor Antibiotic Sibiromycin
作者:Tobias W. Giessen、Femke I. Kraas、Mohamed A. Marahiel
DOI:10.1021/bi2006114
日期:2011.6.28
The antitumor antibiotic sibiromycin belongs to the class of pyrrolo[1,4]benzodiazepines (PBDs) that are produced by a variety of actinomycetes. PBDs are sequence-specific DNA-alkylating agents and possess significant antitumor properties. Among them, sibiromycin, one of two identified glycosylated PBDs, displays the highest DNA binding affinity and the most potent antitumor activity. In this study
抗肿瘤抗生素西伯霉素属于由多种放线菌产生的吡咯并[1,4]苯并二氮杂(PBDs)类。PBD是序列特异性DNA烷基化剂,具有显着的抗肿瘤特性。其中,西比霉素是两种已鉴定的糖基化PBD之一,显示出最高的DNA结合亲和力和最有效的抗肿瘤活性。在这项研究中,我们报道了从已知代谢物3-羟基犬尿氨酸(3HK)开始,阐明了导致在sibiromycin中发现的3,5-二羟基-4-甲基邻氨基苯甲酸构造单元的精确反应序列的过程。研究的途径由四种酶组成,这些酶在体外进行了生化表征。从3HK开始,SAM依赖性甲基转移酶SibL将底物转化为其4-甲基衍生物,然后通过PLP依赖性犬尿氨酸酶SibQ的作用进行水解,导致形成3-羟基-4-甲基邻氨基苯甲酸(3H4MAA)。随后,NRPS二结构域SibE激活3H4MAA,并将其束缚至其硫醇化结构域,在该结构中,其被CAD上的FAD / NADH依赖性羟化酶SibG羟基化