Distribution of charged residues stabilizes individual helices in myoglobins.
Distribution of charged residues stabilizes individual helices in myoglobins.
复制标题
带电残基的分布稳定了肌红蛋白中的各个螺旋。
DOI：
10.1080/07391102.1990.10508536
复制
发表时间：
1990
影响因子：
4.4
通讯作者：
Nelson,JW
中科院分区：
文献类型：
--
作者：
Kallenbach,NR;Lu,M;VasantKumar,N;Nelson,JW
带电残基的分布对α螺旋的稳定性在孤立的肽和球状蛋白质的肌红蛋白从62个不同物种的例子进行了讨论。一套高度简化的规则被用来解释带电基团与α螺旋偶极子的相互作用。只有相对于螺旋中心的电荷的位置和符号及其参与螺旋内盐桥的能力才能决定其效果。这些规则导致来自RNA酶的变体C肽螺旋的螺旋度与电荷分布与螺旋偶极子相反的程度之间的线性相关性。在所研究的肌红蛋白的496个螺旋样本中，有456个呈现出电荷排列，根据这种计算，这些电荷排列与螺旋的有效偶极矩相一致。出现了许多使螺旋A-D的骨架矩不变或甚至增加的变体。然而，在螺旋E-H的序列中不存在这样的变体。我们认为，E，F，G和H螺旋肌红蛋白，其中显示最强的逆转的螺旋偶极子参与早期中间体的结构折叠的链。稳定的螺旋结构应该更有可能发生在这些孤立的序列也，并引入电荷改变螺旋E到H应该会影响突变肌红蛋白的初始重折叠速率。
The effect of the distribution of charged residues on stability of alpha helices in isolated peptides and in globular proteins exemplified by myoglobins from 62 different species is discussed. A highly simplified set of rules is used to account for the interaction of charged groups with the dipole of an alpha helix. Only the position and sign of a charge with respect to the center of the helix and its ability to participate in intrahelical salt bridges determine its effect. These rules lead to a linear correlation between the helicity in variant C-peptide helices from RNAse and the extent to which the charge distribution opposes the helix dipole. Of the sample of 496 helices in the myoglobins studied, 456 exhibit arrangements of charges whichopposethe effective dipole moment of the helix according to this calculation. A number of variants occur which leave the backbone moment of helices A-D unchanged, or even add to it. However no such variants exist in the sequences of helices E-H. We suggest that the E, F, G and H helices in myoglobins which show the strongest reversal of the helix dipole participate in the structures of early intermediates in folding of the chain. Stable helix structures should be more likely to occur in these isolated sequences also, and introduction of charge alterations in helices E to H should affect the initial refolding rate of mutant myoglobins.