Structural forms, stabilities and transitions in double-helical poly(dG-dC) as a function of hydration and NaCl content. An infrared spectroscopic study.

P B Keller; K A Hartman

doi:10.1093/nar/14.20.8167

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Structural forms, stabilities and transitions in double-helical poly(dG-dC) as a function of hydration and NaCl content. An infrared spectroscopic study.

P B Keller·K A Hartman

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Abstract

The poly(dG-dC) helical duplex forms a modified, B-family structure (B*) at very high hydration and a normal B structure at slightly lower hydration. The B* structure is slightly different in sugar-phosphate and base-stacking conformations than the B structure. Increasing the hydration or decreasing the NaCl content stabilizes B* with respect to B. Poly(dG-dC) forms the Z structure at low NaCl contents when the hydration is sufficiently reduced. At moderate NaCl content, the B to Z transition is sharp and cooperative for hydration with D2O. Hydration with H2O broadens the transition which occurs at lower hydration. This suggests that hydrogen bonding is stronger in the Z structure and helps stabilize Z over B. IR spectra may be used to quantitatively estimate the fractions of B and Z structures present in a sample. Some new indicator bands are described.

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DNA Nucleic Acid Conformation Polydeoxyribonucleotides Sodium Chloride Spectrophotometry, Infrared Water Journal Article Research Support, Non-U.S. Gov't

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P B Keller, K A Hartman. 1986-10-24. Structural forms, stabilities and transitions in double-helical poly(dG-dC) as a function of hydration and NaCl content. An infrared spectroscopic study.. https://doi.org/10.1093/nar%2F14.20.8167

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