Padiyar, Sreekanta G and Seshadri, TP (1998) Adenosine-5'-carboxylic Acid. In: Acta Crystollographic Section C Crystal Structure Commumications, 54 (05). pp. 647-649.
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The two molecules in the asymmetric unit of adenosine-5'-carboxylic acid, C10H11N5O5, exist as zwitterions with N1 protonated and the carboxyl groups ionized. Both molecules are in an anti conformation with glycosyl torsion angles of -161.4(3) and -155.5(3)degrees. The ribose moieties adopt a C3-endo-C2-exo twist conformation. The pseudo-rotation parameters are P = 0.01(1) and 6.58(1)degrees, and tau(m) = 36.2(2) and 34.6(2)degrees, for molecules A and B, respectively. The carboxyl groups of A and B are not in the standard g(+), g(-) or t conformations. Both Watson-Crick sites, N1 and N6, of the adenine bases are involved in a pair of hydrogen bonds with the dissociated carboxyl groups, forming a cyclic tetramer. The adenine base of molecule A stacks on the ribose O4' atom of a symmetry-related B molecule at a distance of 2.88 Angstrom; the adenine base of B stacks in an analogous way at a distance of 2.91 Angstrom.
|Item Type:||Journal Article|
|Additional Information:||Copyright of this article belongs to International Union of Crystallography.|
|Department/Centre:||Division of Physical & Mathematical Sciences > Physics|
|Date Deposited:||10 Mar 2009 07:48|
|Last Modified:||19 Sep 2010 05:28|
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