产甲烷古菌铁氢酶研究进展

Advances in[Fe]-hydrogenase from methanogens

摘要:

根据活性中心金属原子的不同，氢酶主要分为镍铁、铁铁、铁氢酶三大类。铁氢酶是发现较晚、存在物种单一且结构较为特殊的一类氢酶。目前，铁氢酶仅发现于氢营养型产甲烷古菌中。该酶直接催化氢气异裂，还原产甲烷代谢途径中一碳载体四氢蝶呤的次甲基转化为亚甲基。与其他两类氢酶相比，铁氢酶不含传递电子的铁硫簇和双金属活性中心，在结构组成上有较大的差异。此外，铁氢酶活性中心的吡啶环被高度取代，活性中心铁原子直接与酰基碳成键，这些奇特的活性分子结构预示着氢酶全新的催化机制，以及古菌细胞在合成特殊结构大分子方面的特殊功能。本文总结了从1990年发现这类新型氢酶以来的相关研究，分别从氢酶的生理功能、结构特征、催化机制、成熟过程及应用研究等方面阐述铁氢酶的研究进展。

Abstract:

Hydrogenases are classified into tree types including[NiFe]-,[FeFe]- and[Fe]-hydrogenase depending on the different metals in the active center.[NiFe]- and[FeFe]-hydrogenases were found in various bacteria, while[Fe]-hydrogenase was only found in hydrogenotrophic methanogens. It catalyzes the hetero cleavage of H₂ to reduce the methenyl group of C1 carrier tetrahydrobiopterin into methylene group. Different from other two types of hydrogenases,[Fe]-hydrogenases do not contain electron-transmitting iron-sulfur clusters and bimetallic active centers. Additionally, the highly substituted pyridine ring and the Fe-acyl carbon bond in active center of[Fe]-hydrogenase indicated that there might be a new catalytic mechanism in hydrogenase. It also proposed that methanogens could synthesis this unique structural cofactor in a special way. This review summarizes the research progress of[Fe]-hydrogenase since its discovery in 1990, including physiological function, structural characteristics, catalytic mechanism, maturation process, and industrial application in future.