Hippler B, Thauer R K
Max-Planck-Institut für terrestrische Mikrobiologie and Laboratorium für Mikrobiologie des Fachbereichs Biologie der Philipps-Universität, Marburg, Germany.
FEBS Lett. 1999 Apr 23;449(2-3):165-8. doi: 10.1016/s0014-5793(99)00429-9.
In methanogenic archaea the transfer of the methyl group of N5-methyltetrahydromethanopterin to coenzyme M is coupled with energy conservation. The reaction is catalyzed by a membrane associated multienzyme complex composed of eight different subunits MtrA-H. The 23 kDa subunit MtrA harbors a corrinoid prosthetic group which is methylated and demethylated in the catalytic cycle. We report here that the 34 kDa subunit MtrH catalyzes the methylation reaction. MtrH was purified and shown to exhibit methyltetrahydromethanopterin:cob(I)alamin methyltransferase activity. Sequence comparison revealed similarity of MtrH with MetH from Escherichia coli and AcsE from Clostridium thermoaceticum: both enzymes exhibit methyltetrahydrofolate:cob(I)alamin methyltransferase activity.
在产甲烷古菌中，N5-甲基四氢甲蝶呤的甲基基团向辅酶M的转移与能量守恒相偶联。该反应由一种与膜相关的多酶复合物催化，该复合物由八个不同的亚基MtrA - H组成。23 kDa的亚基MtrA含有一个类咕啉辅基，其在催化循环中发生甲基化和去甲基化。我们在此报告34 kDa的亚基MtrH催化甲基化反应。MtrH被纯化，并显示具有甲基四氢甲蝶呤：钴胺素（I）甲基转移酶活性。序列比较显示MtrH与大肠杆菌的MetH和热醋梭菌的AcsE具有相似性：这两种酶都具有甲基四氢叶酸：钴胺素（I）甲基转移酶活性。
