Lawhorn Brian G, Mehl Ryan A, Begley Tadhg P
Baker Laboratory, Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.
Org Biomol Chem. 2004 Sep 7;2(17):2538-46. doi: 10.1039/B405429F. Epub 2004 Aug 11.
The conversion of 5-aminoimidazole ribonucleotide (AIR) into 4-amino-2-methyl-5-hydroxymethylpyrimidine (HMP) is a fascinating reaction on the thiamin biosynthetic pathway in bacteria and is probably the most complex unresolved rearrangement in primary metabolism. We have successfully reconstituted this reaction in a cell-free system. The E. coli thiC gene product and an additional unidentified E. coli protein are required for the reaction. In addition, SAM and nicotinamide cofactors are required for full activity. Labeling studies to determine the origin of most of the atoms in the pyrimidine are described. Based on these studies, a new mechanism for HMP formation is proposed.
5-氨基咪唑核糖核苷酸（AIR）转化为4-氨基-2-甲基-5-羟甲基嘧啶（HMP）是细菌硫胺素生物合成途径中一个引人入胜的反应，可能是初级代谢中最复杂的未解决重排反应。我们已在无细胞系统中成功重构了此反应。该反应需要大肠杆菌thiC基因产物和另一种未鉴定的大肠杆菌蛋白质。此外，完整活性还需要SAM和烟酰胺辅因子。本文描述了用于确定嘧啶中大多数原子来源的标记研究。基于这些研究，提出了一种新的HMP形成机制。
