Nitric oxide synthase (NOS) catalyzes the production of nitric oxide from L-arginine and dioxygen at a thiolate-ligated heme active site. Although many of the reaction intermediates are as yet unidentified, it is well established that the catalytic cycle begins with substrate binding and rate-limiting electron transfer to the heme. Here, we show that Ru (II)-diimine and Re (I)-diimine electron tunneling wires trigger nanosecond photoreduction of the active-site heme in the enzyme. Very rapid generation of a reduced thiolate-ligated heme opens the way for direct observation of short-lived intermediates in the NOS reaction cycle.

中文翻译：

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用 Ru(II) 和 Re(I) 电子隧穿线探测诱导型一氧化氮合酶的血红素-硫醇加氧酶结构域

一氧化氮合酶 (NOS) 在硫醇盐连接的血红素活性位点催化 L-精氨酸和分子氧生成一氧化氮。尽管许多反应中间体尚未确定，但已确定催化循环始于底物结合和向血红素的限速电子转移。在这里，我们展示了 Ru (II)-二亚胺和 Re (I)-二亚胺电子隧穿线触发酶中活性位点血红素的纳秒级光还原。还原硫醇结合血红素的快速生成为直接观察 NOS 反应循环中的短寿命中间体开辟了道路。