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Ir vibrational CD in model deoxyoligonucleotides: Observation of the B → Z phase transition and extended coupled oscillator intensity calcuations
Author(s) -
Gulotta Miriam,
Goss Dixie J.,
Diem Max
Publication year - 1989
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.360281202
Subject(s) - chemistry , intensity (physics) , phase transition , phase (matter) , thermodynamics , organic chemistry , quantum mechanics , physics
The first observation of ir vibrational CD (VCD) in small model DNA molecules is reported. The VCD signals in the 1550–1750‐cm −1 spectral region, which originate from coupling of carbonyl stretching modes of the nucleic acid bases, are found to be sensitive to the handedness of the polymer helix. The formalism to calculate VCD intensities of polymers is developed from the exciton model derived earlier by Tinoco [(1963) Radiation Res. 20 , 133; (1960) J. Chem. Phys. 33 , 1332; (1964) J. Am. Chem. Soc. 86 , 297] and Schellman and co‐workers [(1975) Biopolymers 14 , 173; (1969) J. Phys. Chem. 73 , 28]. The resulting equations, which are a direct extension of the dimeric case known as the “coupled oscillator,” are used in model calculations of the helical polymers.