title: Structural transitions in polyribocytidylic acid induced by changes in pH and temperature: vibrational circular dichroism study in solution and film states.
abstract: Changes in vibrational absorption and vibrational circular dichroism (VCD) spectra of polyribocytidylic acid (polyC) in buffered D(2)O solution as a function of pH and temperature are reported. Analysis of these spectral data led us to establish the absorption band at approximately 1693 cm(-1) and associated negative VCD couplet as diagnostic markers of the double-helical form of polyC. An alternate interpretation suggesting quadruplex formation for polyC is also discussed. In addition to the solution state spectral data, pH-dependent absorption and VCD spectra for polyC films derived from dilute H(2)O solutions are also presented. The pH-dependent changes in the absorption and VCD spectra of polyC films are found to be similar to those observed for polyC in solution.
authors.affiliation: Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, USA.
authors.forename: Ana G
authors.initials: AG
authors.lastname: Petrovic
authors.forename: Prasad L
authors.initials: PL
authors.lastname: Polavarapu
mesh_terms: D000042:Absorption; D002942:Circular Dichroism / Q000379:methods*; D017666:Deuterium Oxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D009690:Nucleic Acid Conformation; D011066:Poly C / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry*; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D012996:Solutions; D014867:Water; D011066:Poly C; D017666:Deuterium Oxide