Coupling of ferric iron spin and allosteric equilibrium in hemoglobin.
Coupling of ferric iron spin and allosteric equilibrium in hemoglobin.
复制标题
三价铁自旋与血红蛋白变构平衡的耦合。
DOI：
10.1016/s0006-3495(91)82111-7
复制
发表时间：
1991
影响因子：
3.4
通讯作者：
C. Poyart
中科院分区：
文献类型：
--
作者：
M. Marden;L. Kiger;J. Kister;B. Bohn;C. Poyart
用不同的铁配体研究了三铁血红蛋白的变构转变。这种杂化价允许观察氧或CO与单个亚铁亚基的结合特性，而其他三个亚铁亚基的配体状态可以改变。在没有效应物的情况下，铁血红蛋白（Hb）四聚体通常处于高氧亲和(R)状态；六磷酸肌醇的加入诱导了向脱氧(T)构象的转变。形成的t态的分数取决于铁配体，并与铁配合物的自旋态相关。高自旋铁配体如水或氟化物显示最多的t态，而低自旋配体如氰化物显示最少的t态。氧平衡数据和CO复合动力学表明，变构平衡可以用类似于双态模型的方式处理。低自旋铁配体的结合诱导变构平衡向r态变化约150倍（pH为6.5时），类似于铁配体氧或CO的变化；然而，每个高自旋铁配体诱导T到R的40倍位移。
The allosteric transition in triply ferric hemoglobin has been studied with different ferric ligands. This valency hybrid permits observation of oxygen or CO binding properties to the single ferrous subunit, whereas the liganded state of the other three ferric subunits can be varied. The ferric hemoglobin (Hb) tetramer in the absence of effectors is generally in the high oxygen affinity (R) state; addition of inositol hexaphosphate induces a transition towards the deoxy (T) conformation. The fraction of T-state formed depends on the ferric ligand and is correlated with the spin state of the ferric iron complexes. High-spin ferric ligands such as water or fluoride show the most T-state, whereas low-spin ligands such as cyanide show the least. The oxygen equilibrium data and kinetics of CO recombination indicate that the allosteric equilibrium can be treated in a fashion analogous to the two-state model. The binding of a low-spin ferric ligand induces a change in the allosteric equilibrium towards the R-state by about a factor of 150 (at pH 6.5), similar to that of the ferrous ligands oxygen or CO; however, each high-spin ferric ligand induces a T to R shift by a factor of 40.
影响因子：
2.9
作者：
LALEZARI, I;LALEZARI, P;PERUTZ, MF
通讯作者：
PERUTZ, MF