The biosynthesis of the thiazole phosphate moiety of thiamin (Vitamin B1):: The early steps catalyzed by thiazole synthase
The biosynthesis of the thiazole phosphate moiety of thiamin (Vitamin B1):: The early steps catalyzed by thiazole synthase
复制标题
DOI：
10.1021/ja039616p
复制
发表时间：
2004-03-17
影响因子：
15
通讯作者：
Begley, TP
中科院分区：
文献类型：
--
作者：
Dorrestein, PC;Zhai, HL;Begley, TP
噻唑合酶（ThiG）通过亚胺中间体催化1-脱氧-D-木酮糖-5-磷酸（DXP）的Amadori型重排。为了支持这一点，我们已经证明了酶催化的交换的C2羰基的DXP。硼氢化物还原的酶DXP亚胺，然后由上而下的质谱分析本地化的亚胺赖氨酸96。在此基础上，提出了枯草芽孢杆菌中焦磷酸硫胺素的噻唑磷酸部分生物合成的新机制。该机制涉及通过亚胺的Amadoritype重排在DXP的C3处生成酮，然后将硫载体蛋白（ThiS-硫代羧酸盐）亲核加成到该羰基上。
Thiazole synthase (ThiG) catalyzes an Amadori-type rearrangement of 1-deoxy-D-xylulose-5-phosphate (DXP) via an imine intermediate. In support of this, we have demonstrated enzyme-catalyzed exchange of the C2 carbonyl of DXP. Borohydride reduction of the enzyme DXP imine followed by top-down mass spectrometric analysis localized the imine to lysine 96. On the basis of these observations, a new mechanism for the biosynthesis of the thiazole phosphate moiety of thiamin pyrophosphate in Bacillus subtilis is proposed. This mechanism involves the generation of a ketone at C3 of DXP by an Amadoritype rearrangement of the imine followed by nucleophillic addition of the sulfur carrier protein (ThiS-thiocarboxylate) to this carbonyl group.