title: Infrared and X-ray diffraction study of the effect of protonation of DNA on its B-to-A transition.
abstract: The influence of H+ on the secondary structure of DNA and on its B-to-A transition has been studied by employing X-ray diffraction and infrared spectroscopy. Helical parameters for DNA molecules with different degrees of protonation were determined. It was shown that H+ binding stabilizes the B-form of DNA in fibers over a wide range of water and inorganic salt content. Only 0.03 H+ bound per nucleotide is sufficient to prevent the B-to-A transition caused by decreasing relative humidity in DNA fibers containing 4% NaCl. The effectiveness of B-form stabilization by H+ is explained by changes in DNA-solvent molecule interactions, especially in the major groove of double helices.
authors.affiliation: Institute of Biological Physics, Academy of Sciences of the U.S.S.R., Pushchino, Moscow Region.
authors.forename: B I
authors.initials: BI
authors.lastname: Sukhorukov
authors.forename: M M
authors.initials: MM
authors.lastname: Montrel'
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA; D005399:Fishes; D006863:Hydrogen-Ion Concentration; D008297:Male; D009690:Nucleic Acid Conformation; D011522:Protons; D013055:Spectrophotometry, Infrared / Q000379:methods; D013094:Spermatozoa; D013950:Thymus Gland; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D011522:Protons; D004247:DNA