New light on allostery: dynamic resonance Raman spectroscopy of hemoglobin kempsey.
New light on allostery: dynamic resonance Raman spectroscopy of hemoglobin kempsey.
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DOI：
10.1021/bi982513c
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发表时间：
1999-03
期刊：
影响因子：
2.9
通讯作者：
X. Hu;K. Rodgers;I. Mukerji;T. Spiro
中科院分区：
文献类型：
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作者：
X. Hu;K. Rodgers;I. Mukerji;T. Spiro
基于静态和时间分辨的共振拉曼光谱的HbA和突变体，HbK（Dalpha 99 N），一个特定的反应坐标提出了在人类血红蛋白的变构转换。血红素保持在近端（F）和远端（E）螺旋之间，其取向响应于由连接和脱连接产生的力。E和F螺旋又通过H-键与A和H螺旋连接。这些外螺旋遵循E-F运动，从而重新定位N-和C-末端，其形成T四级结构中的亚基间盐桥。当T状态界面被四元H键（HbK）处的Asp -> Asn取代削弱时，Fe-His键松弛并变得对变构效应物有响应。在HbK中观察到相同的E-F运动，但A-H跟随运动相对于HbA延迟，Asn H-键形成也是如此。
On the basis of static and time-resolved resonance Raman spectroscopy of HbA and of a mutant, HbK (Dalpha99N), a specific reaction coordinate is proposed for the allosteric transition in human hemoglobin. The heme is held between proximal (F) and distal (E) helices, whose orientation is responsive to forces generated by ligation and deligation. The E and F helices are in turn tethered via H-bonds to the A and H helices. These outer helices follow the E-F motion, thereby repositioning the N- and C-termini, which form the intersubunit salt bridges in the T quaternary structure. When the T state interface is weakened by Asp --> Asn substitution at a quaternary H-bond (HbK), the Fe-His bond is relaxed and becomes responsive to allosteric effectors. The same E-F motion is observed in HbK, but the A-H following motion is delayed, relative to HbA, as is the Asn H-bond formation.