Structural transitions in polyriboadenylic acid induced by the changes in pH and temperature: vibrational circular dichroism study in solution and film states.
A correlation of the changes in vibrational absorption and vibrational circular dichroism (VCD) spectral features with the structural changes of polyriboadenylic acid (polyA) as a function of pH is reported. Analysis of the solution spectral data as a function of pH led us to establishing the importance of a previously unrecognized absorption band at approximately 1665 cm(-1). The present studies indicate that this absorption band and associated VCD originate from the double-helical structure of polyA. The observed changes in solution-state VCD features are indicative of the pH-dependent transitions among the three acidic forms of polyA (A, B, and "frozen" form). In addition to the solution-state spectral data, pH-dependent absorption and VCD spectra for films of polyA, derived from dilute H2O solutions, are also presented. The pH-dependent changes in the absorption and VCD spectra of films are also correlated to the polyA structural changes.
Petrovic
Ana G
AG
Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA.
Polavarapu
Prasad L
PL
D002942:Circular Dichroism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D008567:Membranes, Artificial; D015394:Molecular Structure; D011061:Poly A / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry*; D013696:Temperature
D008567:Membranes, Artificial; D012996:Solutions; D011061:Poly A