J. Sussman, N. Seeman, Sung-Hou Kim
May 28, 1972
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Influential Citations
153
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Journal
Journal of molecular biology
Abstract
Abstract The crystal structure of uridylyl 3′,5′-adenosine phosphate (UpA) has been determined and refined to an R value of 0.062. There are two UpA molecules per asymmetric unit in a monoclinic unit cell with dimensions a = 16.91, b = 12.37, c = 11.25 A and β = 96.0 ° . The conformation of the phosphodiester linkage is different for the two molecules; one UpA suggests a model for a sharp turn in a single-stranded nucleic acid structure and the other for a helical structure. All the nucleoside units have similar conformations. There is no complementary base pairing between the adenines and uracils but rather layers of base-paired adenines and base-paired uracils separated by 3.4 A. The predominant form of base stacking involves the ribosyl oxygen atom and the bases.