The probable structure of the protamine–DNA complex

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. eet structure for the protein component is essentially mandated, as the alternatives can be decisively excluded. ric structure too is essentially mandated, since the cysteine residues of protamines P1 and P2 are invariably aligned in all species having both chains. oss-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. it cell of this protamine–DNA complex is essentially devoid of steric hindrances, and heavily favored by a multitude of ionic and hydrogen bonds. cking 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”. ssible significance of the structure beyond the sperm cell is discussed.