White R H
Department of Biochemistry and Anaerobic Microbiology, Virginia Polytechnic Institute and State University, Blacksburg 24061-0308, USA.
Biochemistry. 1996 Mar 19;35(11):3447-56. doi: 10.1021/bi952308m.
This paper establishes the pathway for the biosynthesis of methanopterin in Methanosarcina thermophila to proceed by the following series of reactions. First, 5-phospho-alpha-D-ribosyl diphosphate (PRPP) and 4-aminobenzoic acid condense together to produce 4-(beta-D-ribofuranosyl)aminobenzene 5'-phosphate, which then reacts with 6-hydroxymethyl-7,8-H2pterin pyrophosphate to produce 7,8-H2pterin-6-ylmethyl-4-(beta-D-ribofuranosyl)aminobenz ene 5'-phosphate (3'). Compound 3' is then reduced to 7,8-H2pterin-6-ylmethyl-l-(4-aminophenyl)-1-deoxy-D-ribitol 5'-phosphate (4') in a reaction stimulated by the addition of FMN or factor F(420). Dephosphorylation of compound 4' leads to 7,8-H2pterin-6-ylmethyl-1-(4-aminophenyl)-1-deoxy-D-ribitol (5'). Compound 5' then condenses with another molecule of PRPP to form 7,8-H2pterin-6-ylmethyl-1-(4-aminophenyl)-1-deoxy-5-[1-alpha -D- ribofuranosyl 5-phosphate]-D-ribitol (9'). Compound 9', in the presence of ATP, then condenses with (S)-2-hydroxyglutaric acid to form demethylated H2methanopterin, a known precursor to methanopterin. The occurrence of this pathway was confirmed by (a) the chemical and/or biochemical synthesis of most of the proposed intermediates, (b) the detection of these intermediates in cell-free extracts, and (c) by the measurement of their conversion to demethylated methanopterin and/or other intermediates in the pathway.
本文确定了嗜热甲烷八叠球菌中甲烷蝶呤生物合成的途径，该途径通过以下一系列反应进行。首先，5-磷酸-α-D-核糖基二磷酸（PRPP）与4-氨基苯甲酸缩合生成4-（β-D-呋喃核糖基）氨基苯5'-磷酸，然后它与6-羟甲基-7,8-H2蝶呤焦磷酸反应生成7,8-H2蝶呤-6-基甲基-4-（β-D-呋喃核糖基）氨基苯5'-磷酸（3'）。化合物3'随后在添加FMN或因子F(420)刺激的反应中被还原为7,8-H2蝶呤-6-基甲基-1-（4-氨基苯基）-1-脱氧-D-核糖醇5'-磷酸（4'）。化合物4'的去磷酸化导致生成7,8-H2蝶呤-6-基甲基-1-（4-氨基苯基）-1-脱氧-D-核糖醇（5'）。化合物5'然后与另一分子PRPP缩合形成7,8-H2蝶呤-6-基甲基-1-（4-氨基苯基）-1-脱氧-5-[1-α-D-呋喃核糖基5-磷酸]-D-核糖醇（9'）。在ATP存在下，化合物9'然后与（S）-2-羟基戊二酸缩合形成去甲基化的H2甲烷蝶呤，它是甲烷蝶呤的已知前体。该途径的存在通过以下方式得到证实：（a）大多数提议中间体的化学和/或生物化学合成，（b）在无细胞提取物中检测到这些中间体，以及（c）通过测量它们向去甲基化甲烷蝶呤和/或该途径中其他中间体的转化。
