@article{9e5e861fff02470b831fad30e59aa8bb,
title = "Crystal structure of a naturally occurring dinucleoside phosphate: Uridylyl 3′,5′-adenosine phosphate model for RNA chain folding",
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 {\AA}. The predominant form of base stacking involves the ribosyl oxygen atom and the bases.",
author = "Sussman, {Joel L.} and Seeman, {Nadrian C.} and Kim, {S. H.} and Berman, {Helen M.}",
note = "Funding Information: We thank Alexander Rich (who initially suggested this molecule for study), Jenny Glusker and Cyrus Levinthal for their enoouragemenatn d discussions, and Bud Carrel& Joyce Dsrgay, Reidar Bornholdt, Christo~ Tountas and John Geneva for technical and programming assistance. We are gratiful to Hilger $1 Watts Ltd., London, and General Electric Company for the use of their automatic diffractometers, and to the Graph& Facility for Interactive Displays direoted by LOU Katz and the Computer Center at Columbia University for the use of their computers. This research was supported in part by U.S. Public Health Service grants CA10925, CA06927, CA04186 3P07RROO442 and a trainin g gram in biophysics STOlGMO2012 from the National Institutes of Health; GBlb754 and GB18421 from the National Science Foundation; E247B from the American Cancer Society and by an appropriation from the Commonwealth of Pennsylvania. This work was submitted by one of us (J.L.S.) in partial fulfillment of the requirements for the PhD degree at Massachusetts Institute of Technology.",
year = "1972",
month = may,
day = "28",
doi = "10.1016/0022-2836(72)90423-8",
language = "English (US)",
volume = "66",
pages = "403--421",
journal = "Journal of Molecular Biology",
issn = "0022-2836",
publisher = "Academic Press Inc.",
number = "3",
}