Premium
A temperature‐dependent Z to B to single‐strand transition in d(CGCG)
Author(s) -
Thomas Gerald A.,
Peticolas Warner L.
Publication year - 1989
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.360280911
Subject(s) - chemistry , divalent , ion , stacking , crystallography , population , dissociation (chemistry) , transition temperature , stereochemistry , organic chemistry , physics , superconductivity , quantum mechanics , demography , sociology
A thermally induced left‐ to right‐handed helical interconversion for the self‐complementary tetradeoxynucleotide d(CGCG) has been observed in the presence of NaCl at concentrations from 1.5 to 2.25 M . Analysis of the Raman spectrum of d(CGCG) in aqueous solution as a function of temperature indicates that at low temperature a left‐handed Z‐helical form is the predominant species. An increase in temperature results in a decrease in the population of the left‐handed form and an increase in the population of the right‐handed form. Further elevation in temperature results in extensive disruption of base stacking and a loss of secondary structure. This unstacking presumably represents dissociation to a single‐stranded structure. The data suggest that a temperature‐dependent Z to B to single‐strand transition occurs under the conditions employed. A direct Z to single‐strand conversion was not identified. In contrast to previous examples, the thermally induced left‐ to right‐handed helical conversion for d(CGCG) can occur in the absence of chemically modified nucleic acid bases, alcohol solutions, or divalent ions.