MODEL FOR THE STRUCTURE OF NUCLEOPROTAMINE

被引：16

作者：

BAZETTJONES, DP ^{[1
]}

OTTENSMEYER, FP ^{[1
]}

机构：

[1] ONTARIO CANC INST,TORONTO M4X 1K9,ONTARIO,CANADA

来源：

JOURNAL OF ULTRASTRUCTURE RESEARCH | 1979年 / 67卷 / 03期

基金：

英国医学研究理事会;

关键词：

D O I：

10.1016/S0022-5320(79)80026-X

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

A model for the structure of nucleoprotamine is presented, based on dark-field and bright-field electron micrographs of complexes of fish protamine and λDNA reconstituted in vitro. It is proposed that the protamine molecule, an ellipsoidal molecule with a comb- or star-shaped appearance, acts as a core around which the DNA double helix is wound or supercoiled, one supercoil turn per protamine molecule. The loops of the right-handed supercoil, lying side by side, are composed of about 40 base pairs of DNA and have an outer diameter of about 60 Å. This structure appears to form the first-order packing of DNA by protamine, with a packing ratio of about 4.2. An extension of the first-order model, in which adjacent supercoiled regions of the DNA lie parallel to each other, satisfies X-ray diffraction data on nucleoprotamine. © 1979 Academic Press, Inc.

引用

页码：255 / 266

页数：12

共 17 条

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