Rates of energy transfer between tryptophans and hemes in hemoglobin, assuming that the heme is a planar oscillator.
Rates of energy transfer between tryptophans and hemes in hemoglobin, assuming that the heme is a planar oscillator.
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血红蛋白中色氨酸和血红素之间的能量转移率（假设血红素是平面振荡器）。
DOI：
10.1016/s0006-3495(92)81657-0
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发表时间：
1992
影响因子：
3.4
通讯作者：
Bucci,E
中科院分区：
文献类型：
--
作者：
Gryczynski,Z;Tenenholz,T;Bucci,E
使用福斯特方程，我们估计了血红蛋白中从色氨酸到血红素的能量转移速率。假设血红素的转变矩在卟啉平面上呈各向同性分布，我们根据人氧合血红蛋白和脱氧血红蛋白的晶体坐标计算了取向因子和随后的转移速率。看来定向因素在调节能量转移中并没有发挥限制作用，并且速率几乎完全由色氨酸和血红素之间的亚基内分离控制。在完整的血红蛋白四聚体中，亚基内分离使得色氨酸寿命缩短至 5 和 15 ps/ns。亚基间分离将允许数百皮秒的寿命，但仅当每个四聚体不存在一个血红素或不接受转移时，亚基间转移才变得重要。如果每个四聚体缺少一个以上的血红素，则会出现超过 1 ns 的寿命。
Using the Förster equations we have estimated the rate of energy transfer from tryptophans to hemes in hemoglobin. Assuming an isotropic distribution of the transition moments of the heme in the plane of the porphyrin, we computed the orientation factors and the consequent transfer rates from the crystallographic coordinates of human oxy- and deoxy-hemoglobin. It appears that the orientation factors do not play a limiting role in regulating the energy transfer and that the rates are controlled almost exclusively by the intrasubunit separations between tryptophans and hemes. In intact hemoglobin tetramers the intrasubunit separations are such as to reduce lifetimes to 5 and 15 ps/ns of tryptophan lifetime. Lifetimes of several hundred picoseconds would be allowed by the intersubunit separations, but intersubunits transfer becomes important only when one heme per tetramer is absent or does not accept transfer. If more than one heme per tetramer is absent lifetimes of more than 1 ns would appear.