White R H
Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061-0308, USA.
Biochim Biophys Acta. 1998 Apr 10;1380(2):257-67. doi: 10.1016/s0304-4165(97)00148-7.
The basic scheme for the biosynthesis of methanopterin (MPT) in Methanobacterium thermoautotrophicum strain DeltaH, and M. thermoautotrophicum strain Marburg, has been shown to be the same as that recently determined for Methanosarcina thermophila strain TM-1. This scheme has, as one of its unique steps, the condensation of 4-aminobenzoic acid with 5-phospho-alpha-d-ribosyl diphosphate (PRPP) to form 4-(beta-d-ribofuranosyl)aminobenzene 5'-phosphate (beta-RFA-P). Labeling experiments with each of these organisms have established that the sites in the overall sequence of reactions from beta-RFA-P to MPT, where the S-adenosylmethionine-dependent C-9 and C-7 methylations of the pterin-containing intermediates occur, are organism related. In this work, cell extracts of M. thermoautotrophicum strain DeltaH, and M. thermoautotrophicum strain Marburg were found to contain significant amounts of methanopterin lacking the phosphate and 2-hydroxyglutaric acid groups.
嗜热自养甲烷杆菌DeltaH菌株和嗜热自养甲烷杆菌马尔堡菌株中，甲蝶呤（MPT）生物合成的基本方案已被证明与最近确定的嗜热嗜甲基菌TM-1菌株相同。该方案有一个独特步骤，即4-氨基苯甲酸与5-磷酸-α-D-核糖基二磷酸（PRPP）缩合形成4-（β-D-呋喃核糖基）氨基苯5'-磷酸（β-RFA-P）。对这些生物体分别进行的标记实验已证实，从β-RFA-P到MPT的整个反应序列中，含蝶呤中间体的S-腺苷甲硫氨酸依赖性C-9和C-7甲基化发生的位点与生物体有关。在这项研究中，发现嗜热自养甲烷杆菌DeltaH菌株和嗜热自养甲烷杆菌马尔堡菌株的细胞提取物中含有大量缺乏磷酸基团和2-羟基戊二酸基团的甲蝶呤。
