Kinetic Modulation in Carbonmonoxy Derivatives of Truncated Hemoglobins
Kinetic Modulation in Carbonmonoxy Derivatives of Truncated Hemoglobins
复制标题
截短血红蛋白一碳氧衍生物的动力学调节
DOI：
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发表时间：
2003
影响因子：
4.8
通讯作者：
J. Friedman
中科院分区：
文献类型：
--
作者：
U. Samuni;D. Dantsker;Anandhi Ray;J. Wittenberg;B. Wittenberg;S. Dewilde;L. Moens;Yannick H Ouellet;M. Guertin;J. Friedman
截短血红蛋白（Truncated hemoglobins，trHbs）是一类新发现的肌红蛋白样蛋白，广泛存在于细菌、单细胞真核生物和高等植物中。与trHbs相关的显著和独特的特征包括远端血红素口袋内的氢键网络和将外部溶剂连接到远端血红素口袋的长非极性隧道。本工作比较了两个trHb，一个来自纤毛原生动物草履虫尾状草履虫（P-trHb）和另一个来自绿色衣原体真配子体（C-trHb）的双生和溶剂相的再结合动力学。观察到不寻常的动力学模式，包括指示超快（皮秒）的成对再结合的CO到C-TRHb，非常快的溶剂相再结合的CO为两个TRHBS，时间依赖性的两相CO再结合动力学P-TRHb在低CO分压，和P-TRHb，在高粘度条件下的成对产率从百分之几增加到近100%。在8-ns的光解离量子产率和再结合动力学的物种特异性差异，点E11残基的关键功能作用。温度，配体浓度和粘度（甘油，海藻糖）和粘度依赖性的变化，在共振拉曼光谱的配位的photoproduct的再结合动力学的响应，一起牵连的非极性隧道和静态和动态特性的氢键网络内的远端血红素口袋中产生不寻常的动力学模式观察到这些trHbs。
Truncated hemoglobins (trHbs), are a distinct and newly characterized class of small myoglobin-like proteins that are widely distributed in bacteria, unicellular eukaryotes, and higher plants. Notable and distinctive features associated with trHbs include a hydrogen-bonding network within the distal heme pocket and a long apolar tunnel linking the external solvent to the distal heme pocket. The present work compares the geminate and solvent phase rebinding kinetics from two trHbs, one from the ciliated protozoan Paramecium caudatum (P-trHb) and the other from the green alga Chlamydomonas eugametos (C-trHb). Unusual kinetic patterns are observed including indications of ultrafast (picosecond) geminate rebinding of CO to C-trHb, very fast solvent phase rebinding of CO for both trHbs, time-dependent biphasic CO rebinding kinetics for P-trHb at low CO partial pressures, and for P-trHb, an increase in the geminate yield from a few percent to nearly 100% under high viscosity conditions. Species-specific differences in both the 8-ns photodissociation quantum yield and the rebinding kinetics, point to a pivotal functional role for the E11 residue. The response of the rebinding kinetics to temperature, ligand concentration, and viscosity (glycerol, trehalose) and the viscosity-dependent changes in the resonance Raman spectrum of the liganded photoproduct, together implicate both the apolar tunnel and the static and dynamic properties of the hydrogen-bonding network within the distal heme pocket in generating the unusual kinetic patterns observed for these trHbs.
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影响因子：
2.9
作者：
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通讯作者：
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影响因子：
2.9
作者：
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通讯作者：
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影响因子：
2.9
作者：
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通讯作者：
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影响因子：
2.9
作者：
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通讯作者：
PETSKO, GA
影响因子：
2.9
作者：
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通讯作者：
T. K. Das;R. Weber;S. Dewilde;J. Wittenberg;B. Wittenberg;K. Yamauchi;M. Van Hauwaert;L. Moens;D. Rousseau