Ammonia production at the FeMo cofactor of nitrogenase:: Results from density functional theory
Ammonia production at the FeMo cofactor of nitrogenase:: Results from density functional theory
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DOI：
10.1021/ja068618h
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发表时间：
2007-03-14
影响因子：
15
通讯作者：
Bloechl, Peter E.
中科院分区：
文献类型：
--
作者：
Kaestner, Johannes;Bloechl, Peter E.
生物固氮已经被研究，从单质子化的二氮结合到氮酶的FeMo辅因子，直到两个氨分子的形成。介绍了相关中间体的能量差、反应势垒和可能相关的侧支。在催化转化过程中，氮桥接中心笼的两个铁原子，取代了二氮与辅因子结合之前存在的硫桥。发现了顺式二氮烯向反式二氮烯的转变。当铁原子被单个氮原子桥接时，二氮键发生了强烈的放热裂解。在分子内质子转移后，硫桥的关闭促进了第二氨与辅因子的解离。这就结束了催化循环。
Biological nitrogen fixation has been investigated beginning with the monoprotonated dinitrogen bound to the FeMo cofactor of nitrogenase up to the formation of the two ammonia molecules. The energy differences of the relevant intermediates, the reaction barriers, and potentially relevant side branches are presented. During the catalytic conversion, nitrogen bridges two Fe atoms of the central cage, replacing a sulfur bridge present before dinitrogen binds to the cofactor. A transformation from cis- to trans-diazene has been found. The strongly exothermic cleavage of the dinitrogen bond takes place, while the Fe atoms are bridged by a single nitrogen atom. The dissociation of the second ammonia from the cofactor is facilitated by the closing of the sulfur bridge following an intramolecular proton transfer. This closes the catalytic cycle.