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Dielectric study on hydration of B‐, A‐, and Z‐DNA
Author(s) -
Umehara Toshihiro,
Kuwabara Shinichi,
Mashimo Satoru,
Yagihara Shin
Publication year - 1990
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.360300702
Subject(s) - bound water , chemistry , molecule , dna , dielectric , z dna , relaxation (psychology) , nucleotide , phosphate , crystallography , phosphate buffered saline , stereochemistry , chemical physics , biochemistry , organic chemistry , chromatography , materials science , social psychology , psychology , optoelectronics , gene
Dielectric relaxation peak due to bound water was found around 100 MHz in poly(dG‐dC) · poly(dG‐dC) and calf thymus DNA in water–ethanol mixtures with NaCl buffer. Relaxation time and strength show a transition for poly(dG‐dC) · poly(dG‐dC) at anethanol composition C w = 0.45 (w/w) where the structural transition from B‐ to Z‐DNA takes place. It has been suggested that the transition is caused by removal of the bound water molecules preferentially from the phosphate groups. If the bound water molecules are removed equally from the phosphate groups and the grooves, the structural transition from B to A takes place. By analogy with hydration of tropocollagen, it was found that 19 water molecules per one nucleotide are at least necessary to keep B‐DNA. Thirteen molecules are bound to A‐DNA and 9 molecules to Z‐DNA. Stringlike multimers are proposed as available structures of the bound water.