Theory of helix-coil transitions involving complementary poly- and oligo-nucleotides. I. The complete binding case

Autor: Julian H. Gibbs, Bruno H. Zimm, William S. Magee
Rok vydání: 1963
Předmět:
Zdroj: Biopolymers. 1:133-143
ISSN: 1097-0282
0006-3525
DOI: 10.1002/bip.360010204
Popis: A statistical thermodynamic treatment of thermally induced helix–coil transitions is formulated with the matrix method for an (ensemble) of system(s) in which one strand of a double helix consists of a homopolymeric polynucleotide and the other strand comprises a number of complementary oligonucleotides. Each oligonucleotide is considered to be completely bound to the longer chain when in the helical configuration and completely free from it when in the randomly coiled configuration. The case of partial binding; i.e., “dangling,” is treated in a later paper. Taken into account in both cases are intrachain “stacking” interactions between nearest neighbor residues and interchain hydrogen bonding. An approximate treatment of the characteristic equation of the formulation indicates that the reciprocal of the transition temperature (1/T0) is a linear function of the reciprocal of the degree of polymerization (D.P.) of the oligonucleotides. In the same approximation, 1/T0 is also a linear function of the negative logarithm of the absolute activity of the oligonucleotides. Transition curves obtained by exact calculation on a computer are presented for various degrees of polymerization of both the oligo- and polynucleotides. These curves show a sharpening of the transition with increasing D.P. of the long chain and the aforementioned reciprocal D.P. dependence of 1/T0.
Databáze: OpenAIRE
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