Ligand binding to heme proteins: the effect of light on ligand binding in myoglobin.
Ligand binding to heme proteins: the effect of light on ligand binding in myoglobin.
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配体与血红素蛋白的结合：光对肌红蛋白中配体结合的影响。
DOI：
10.1021/bi00249a030
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发表时间：
1994
期刊：
影响因子：
2.9
通讯作者：
Frauenfelder,H
中科院分区：
文献类型：
--
作者：
Nienhaus,GU;Mourant,JR;Chu,K;Frauenfelder,H
摘要：延长光照可减缓CO在低温下光解后与肌红蛋白的再结合。已经提出了两种类型的模型来解释这种影响：血红素口袋内CO的运动或蛋白质的构象转变。为了解决这一歧义，我们利用温度导数光谱研究了扩展照明对马和抹香鲸肌红蛋白（hMb和swMb）配体结合的影响，监测了CO拉伸带和构象敏感带III在760 nm附近的反应。实验表明，光解CO的拉伸频率在光照条件下没有变化，表明CO再结合的减缓是由Mb从束缚态向脱氧结构的构象弛豫引起的。光致弛豫（LIR）取决于吸收光子的数量，而不取决于光强或持续时间。LIR发生在束缚态或光解态的光子吸收上，并取决于MbCO被照射的温度。LIR通过少量构象亚态进行跳跃。再结合的有效屏障随着每一步的增加而增加。填充的基态与在160 K以上观察到的热诱导弛豫（TIR）中发现的相似。LIR明显取决于结构细节；对于swMbCO和hMbCO，甚至swMbCO的三个A基态都是不同的。MbCO和MbOa的效果存在明显差异。LIR和TIR的相似性导致了配体与swMbCO和hMbCO结合的修正模型，其中松弛对于配体从口袋中逃逸至关重要，这是Friedman首先提出的[Friedman， J. M.(1985) Science 228, 1273-1280]。
Revised Manuscript Received August 23, 1994® abstract: Extended illumination slows the rebinding of CO to myoglobin after photodissociation at cryogenic temperatures. Two types of models have been putforward to explain the effect: motions of the CO within the heme pocket or conformational transitions of the protein. To resolve thisambiguity, we have studied the effect of extended illumination on ligand binding tohorse and sperm whale myoglobin (hMb and swMb) with temperature-derivative spectroscopy, monitoring the reactionin the CO stretch bands in the infrared and the conformation-sensitive band III near 760 nm. The experiments show that the stretch frequency of the photodissociated CO does not change upon illumination, implying that the slowing of the CO rebinding is caused byconformational relaxation of Mb from the bound state toward the deoxy structure. The light-induced relaxation (LIR) depends on the number of photons absorbed but not on the light intensity or duration separately. LIR occurs on photon absorption in either the bound or photodissociated state and depends on the temperature at which the MbCO is illuminated. The LIR proceeds in jumps through a small number of conformational substates. The effective barrier for rebinding increases with each step. The substates populated are similar to those found in the thermally-induced relaxation (TIR) that is observed above 160 K. LIR depends markedly on the structural details; it differs for swMbCO and hMbCO and even for the three A substates of swMbCO. Pronounced differences exist betweenthe effects in MbCO and MbOa. The similarity of LIR and TIR leads to a revised model for ligand binding to swMbCO and hMbCO, in which the relaxation is crucial for the escape of the ligand from the pocket, as was first suggested by Friedman [Friedman, J. M.(1985) Science 228, 1273—1280].
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血红素蛋白配体特异性近端控制的证据：配体结合肌红蛋白低温捕获光产物的吸收和拉曼研究☆
影响因子：
2.9
作者：
A. Ahmed;B. Campbell;D. Caruso;M. Chance;M. D. Chavez;S. H. Courtney;J. Friedman;I. Iben;M. Ondrias;M. Yang
通讯作者：
M. Yang
与马肌红蛋白结合的结构弛豫和非指数动力学。
影响因子：
3.4
作者：
F. Post;W. Doster;G. Karvounis;M. Settles
通讯作者：
M. Settles
影响因子：
3.8
作者：
ANSARI, A;BERENDZEN, J;YOUNG, RD
通讯作者：
YOUNG, RD
DOI：
10.1073/pnas.82.15.5000
发表时间：
1985-01-01
影响因子：
11.1
作者：
ANSARI, A;BERENDZEN, J;YOUNG, RD
通讯作者：
YOUNG, RD
影响因子：
2.9
作者：
BEECE, D;EISENSTEIN, L;YUE, KT
通讯作者：
YUE, KT