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The flexible DNA double helix. II. Superhelix formation
Author(s) -
Olson Wilma K.
Publication year - 1979
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1979.360180515
Subject(s) - superhelix , chemistry , phosphodiester bond , polynucleotide , helix (gastropod) , folding (dsp implementation) , crystallography , dna , nucleosome , protein secondary structure , dna supercoil , chromatin , rna , dna replication , biochemistry , structural engineering , ecology , biology , snail , gene , engineering
A simple super or s‐virtual bond scheme has been developed for the treatment of tertiary or superhelical structure in polynucleotide chains. The various spatial configurations accessible to the flexible double helix are rendered more readily intelligible by the introduction of these hypothetical bonds to replace real sequences of regular secondary structure. The scheme is utilized to examine the enormous variety of tertiary structure that can be generated by regularly bending a B‐DNA reference helix at the phosphodiester linkages. Of particular interest from the study are the large families of bends that generate superhelices of identical macroscopic dimensions. Various modes of folding the B‐type helix into superhelices that fit the experimentally measured dimensions of chromatin nucleosomes are illustrated.