Structure of the beta-form of poly d(A).poly d(U).
The crystalline beta-form of the sodium salt of poly d(A).poly d(U) trapped in oriented fibers forms a Watson-Crick base-paired, 10(1) double-helix of pitch 3.2 nm. Two molecules are present in a monoclinic unit cell apparently isomorphous with beta-poly d(A).poly d(T). The two chains in each molecule both carry C2'-endo puckered furanose rings but are conformationally not identical. The orientations of the A:U base-pairs relative to the helix-axis are distinctly different from those in classical B-DNA and the overall morphology of the duplex in which they reside resembles that of the alpha-forms of poly (purine).poly (pyrimidine) DNA duplexes previously reported.
Chandrasekaran
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R
Whistler Center, Purdue University West Lafayette, Indiana 47907.
Radha
A
A
Park
H S
HS
Arnott
S
S
D004247:DNA; D006860:Hydrogen Bonding; D008958:Models, Molecular; D015394:Molecular Structure; D009690:Nucleic Acid Conformation; D011061:Poly A; D011072:Poly U; D014961:X-Ray Diffraction
D011061:Poly A; C015465:poly(dA); D011072:Poly U; D004247:DNA