Premium
Volume changes accompanying the complex formation of polyadenylic and polyuridylic acids
Author(s) -
Noguchi Hajime,
Arya Suresh K.,
Yang Jen Tsi
Publication year - 1971
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.360101210
Subject(s) - chemistry , polynucleotide , protonation , counterion , residue (chemistry) , solvent , nucleotide , helix (gastropod) , mole , volume (thermodynamics) , polyelectrolyte , stereochemistry , crystallography , organic chemistry , ion , biochemistry , thermodynamics , ecology , physics , polymer , biology , snail , gene
The complex formation of polyadenylic acid (poly A) and polyuridylic acid (poly U) in 0.1 M NaCl solution containing 0.01 M sodium cacodylate was followed by dilatometric measurements at various mixing ratios of poly A and poly U. The volume changes, Δ V , accompanying the formation of poly A. poly U and poly A.2poly U were + l.5 and + 2.5 ml per mole of the nucleotide residue, respectively. This increase in volume was probably due to the increased counterion binding when the single‐stranded polynucleotides were converted into the double‐ and triple‐stranded helices, since depletion of charged species from the solvent proper would lessen the effect of electrostriction, thus resulting in a positive Δ V. The conversion of a single‐stranded poly A to a double‐stranded helix in acidic solution led to a Δ V of + 3.8 ml per mole of the nucleotide residue. This increase in volume was attributed to the charge neutralization as a result of protonation of the adenine bases.