Does DNA adopt the C form in concentrated salt solutions or in organic solvent water mixtures? An x-ray diffraction study of DNA fibers immersed in various media.

摘要: Abstract It has previously been proposed (Nelson & Johnson, 1970; Green Mahler, 1971; Girod et al. , 1973; Tunis-Schneider Maestre, Hanlon 1975) that several organic solvents and concentrated salt solutions convert DNA into the C form. This assignment is based upon similarity of circular dichroism spectra in these media to spectrum attributed We have looked for presence form fibers immersed media, using characteristic X-ray diffraction pattern as an assay DNA. In most cases, however, adopted B rather than discrepancy appears arise from incorrect certain clearly do adopt on their patterns. structures a greater helical rotation per residue those had noted by Marvin (1961), so extend range which may be termed The surveyed included salts (NaCl, LiCl, NH 4 Cl, KCl or guanidinium · HCl) well number (methanol, ethanol, t -butanol, ethylene glycol glycerol) either alone mixtures with water. behavior sodium lithium were compared instances. Fibers bacteriophage T4 examined cause salmon A extreme contrast this ability undergo large conformational changes, was characterized relatively restricted presumably due steric restrictions its glucosylated residues.