Open AccessHelical parameters of DNA do not change when DNA fibers are wetted: X-ray diffraction study.
Author(s) -
Steven B. Zimmerman,
Barbara H. Pheiffer
Publication year - 1979
Publication title -
proceedings of the national academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.76.6.2703
Subject(s) - diffraction , fiber diffraction , dna , residue (chemistry) , dissolution , x ray crystallography , crystallography , molecule , chemistry , capillary action , base pair , fiber , materials science , analytical chemistry (journal) , chromatography , optics , biochemistry , physics , composite material , organic chemistry
We have measured the helical parameters of DNA in concentrated solutions by x-ray fiber diffraction methods. Fibers of the sodium salt of DNA were swollen with water within capillaries; the capillary served to limit water uptake, slowing dissolution. Samples containing up to 80% water gave essentially a B-form diffraction pattern and had virtually the same helical parameters [9.91 base pairs per turn (SD = 0.14); 3.34 A axial rise per residue (SD = 0.019)] as did the initial fibers [9.95 base pairs per turn (SD = 0.15); 3.33 A axial rise per residue (SD = 0.015)]. Hence, under highly solvated conditions in which the interactions between molecules should be greatly decreased, DNA maintains its classical B-form structure.
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