PICOSECOND INFRARED STUDY OF THE PHOTODYNAMICS OF CARBONMONOXY-CYTOCHROME-C OXIDASE
PICOSECOND INFRARED STUDY OF THE PHOTODYNAMICS OF CARBONMONOXY-CYTOCHROME-C OXIDASE
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DOI：
10.1021/bi00168a015
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发表时间：
1994-01-18
期刊：
影响因子：
2.9
通讯作者：
WOODRUFF, WH
中科院分区：
文献类型：
--
作者：
DYER, RB;PETERSON, KA;WOODRUFF, WH
时间分辨红外（TRIR）技术已被用来研究一氧化碳与细胞色素c氧化酶（CcO）的细胞色素a3-Cu（B）位点的反应。使用皮秒 TRIR 光谱和线性二色性研究了光解离后立即的连接动力学。通过监测瞬态 Cu(B)CO 吸收的发展，直接测量 CO 从细胞色素 a3 到 Cu(B) 的光引发转移速率。在不到 1 ps 的时间内，就会形成稳定的 Cu(B)CO 光谱，该光谱与 CO 红外线性二色性一起保持恒定，直到 CO 在微秒时间尺度上从 Cu(B) 解离。这些观察结果表明 CO 在金属之间转移并在不到 1 ps 的时间内达到其平衡构象。这种前所未有的配体转移率对于细胞色素 a3-CU(B) 位点的结构和动力学、蛋白质的功能结构以及一般的协调动力学具有深远的影响。
Time-resolved infrared (TRIR) techniques have been employed to study the reactions of carbon monoxide with the cytochrome a3-Cu(B) site of cytochrome c oxidase(CcO). The ligation dynamics immediately following photodissociation have been investigated using picosecond TRIR spectroscopy and linear dichroism. The rate of photoinitiated transfer of CO from cytochrome a3 to Cu(B) was measured directly by monitoring the development of the transient Cu(B)CO absorption. In less than 1 ps, a stationary Cu(B)CO spectrum develops, which together with the CO infrared linear dichroism is constant until the CO dissociates from Cu(B) on a microsecond time scale. These observations indicate that the CO is transferred between metals and reaches its equilibrium conformation in less than 1 ps. This unprecedented ligand transfer rate has profound implications with regard to the structure and dynamics of the cytochrome a3-CU(B) site, the functional architecture of the protein, and coordination dynamics in general.