Volume changes accompanying the complex formation of polyadenylic and polyuridylic acids

✍ Scribed by Hajime Noguchi; Suresh K. Arya; Jen Tsi Yang

• Publisher: Wiley (John Wiley & Sons)
• Year: 1971
• Tongue: English
• Weight: 441 KB
• Volume: 10
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.360101210

✦ Synopsis

The complex formation of polyadenylic acid (poly A ) arid polyuridylic acid (poly U) in 0.1M NaCl solritioti containing 0.01M sodium cacodylate was followed by dilatometric nieasurenieiits a t various mixing ratios of poly A and poly Ti. The volume changes, 3 V , accompanying the formation of poly A . poly U and poly A . 2poly U were + 1.5 arid +2.5 nil per mole of the iiricleotkie residue, respectively. This increase in volume was probably drie to the increased coririterion binding when the single-st rarided polyriucleot,ides were converted into the double-and t.riple-stmnded helices, since depletioii of charged species from the solvent proper would lessen the effect, of electrostrictiori, thus resnlt.irig i i i a positive A 1'. The conversion of a single-stranded poly A to a double-stranded helix in acidic solution led to a AV of +3.8 ml per mole of the nucleotide residue. This iiicrease in voliime was attributed to the charge rieiitralization as a result of protoriation of the adenine bases.