The probable structure of the protamine-DNA complex
The probable structure of the protamine-DNA complex
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DOI：
10.1016/j.jtbi.2005.12.015
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发表时间：
2006-08-07
影响因子：
2
通讯作者：
Biegeleisen, Ken
中科院分区：
文献类型：
--
作者：
Biegeleisen, Ken
一个详细的分子结构提出了人类鱼精蛋白-DNA复合物，这在很大程度上是一个谜。该结构是用虚拟建模软件创建的（AmiraMol），采用逻辑推理作为主要的研究工具。蛋白质组分的β折叠结构基本上是强制性的，因为替代物可以被决定性地排除。二聚体结构也基本上是强制性的，因为鱼精蛋白P1和P2的半胱氨酸残基在具有两条链的所有物种中总是对齐的。根据Wu提出的DNA结构，该蛋白质结构中精氨酸胍基的截面和轴向间距可以与DNA中磷酸基的截面和轴向间距完美地对齐。这是一种非螺旋结构，实验观察表明其可能存在于某些质粒中。这种鱼精蛋白-DNA复合物的晶胞基本上没有空间障碍，并且受到大量离子键和氢键的青睐。鱼精蛋白-DNA结构的相邻“晶胞”的包装是基于盐桥的复杂阵列，它的存在是如此的偶然，以至于它几乎是不可想象的，它仅仅是通过一个模型的“巧合”来实现的。2讨论了该结构在精子细胞之外的可能意义。(c)2006爱思唯尔有限公司保留所有权利。
A detailed molecular structure is proposed for the human protamine-DNA complex, which has hitherto been largely a mystery. The structure was created with virtual modeling software (AmiraMol), employing logical deduction as the primary investigative tool.A beta-sheet structure for the protein component is essentially mandated, as the alternatives can be decisively excluded.A dimeric structure too is essentially mandated, since the cysteine residues of protamines P1 and P2 are invariably aligned in all species having both chains.The cross-sectional and axial spacings of arginine guanidinium groups in this protein structure can be perfectly aligned with those of phosphate groups in DNA according to the DNA structure proposed by Wu. This is a non-helical structure, whose possible occurrence in certain plasmids has been suggested by experimental observations.The unit cell of this protamine-DNA complex is essentially devoid of steric hindrances, and heavily favored by a multitude of ionic and hydrogen bonds.The packing of adjacent "unit cells" of the protamine-DNA structure is based on a complex array of salt bridges, the mere existence of which is so fortuitous that it is virtually inconceivable that it comes about through a mere modeling "coincidence".The possible significance of the structure beyond the sperm cell is discussed. (c) 2006 Elsevier Ltd. All rights reserved.