title: Different nucleobase orientations in two cyclic 2',3'-phosphates of purine ribonucleosides: Et(3)NH(2',3'-cAMP) and Et(3)NH(2',3'-cGMP)xH(2)O.
abstract: The crystal structures of triethylammonium adenosine cyclic 2',3'-phosphate {systematic name: triethylammonium 4-(6-aminopurin-9-yl)-6-hydroxymethyl-2-oxido-2-oxoperhydrofurano[3,4-c][1,3,2]dioxaphosphole}, Et(3)NH(2',3'-cAMP) or C(6)H(16)N(+).C(10)H(11)N(5)O(6)P(-), (I), and guanosine cyclic 2',3'-phosphate monohydrate {systematic name: triethylammonium 6-hydroxymethyl-2-oxido-2-oxo-4-(6-oxo-1,6-dihydropurin-9-yl)perhydrofurano[3,4-c][1,3,2]dioxaphosphole monohydrate}, [Et(3)NH(2',3'-cGMP)].H(2)O or C(6)H(16)N(+).C(10)H(11)N(5)O(7)P(-).H(2)O, (II), reveal different nucleobase orientations, viz. anti in (I) and syn in (II). These are stabilized by different inter- and intramolecular hydrogen bonds. The structures also exhibit different ribose ring puckering [(4)E in (I) and (3)T(2) in (II)] and slightly different 1,3,2-dioxaphospholane ring conformations, viz. envelope in (I) and puckered in (II). Infinite ribbons of 2',3'-cAMP(-) and helical chains of 2',3'-cGMP(-) ions, both formed by O-H...O, N-H...X and C-H...X (X = O or N) hydrogen-bond contacts, characterize (I) and (II), respectively.
authors.affiliation: Faculty of Chemistry, University of Wrocław, 14 Joliot-Curie St, 50-383 Wrocław, Poland. kris@wcheto.chem.uni.wroc.pl
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Sierosławski
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Slepokura
authors.forename: Tadeusz
authors.initials: T
authors.lastname: Lis
authors.forename: Małgorzata
authors.initials: M
authors.lastname: Bogucka
authors.forename: Joanna
authors.initials: J
authors.lastname: Lutomska
authors.forename: Adam
authors.initials: A
authors.lastname: Kraszewski
mesh_terms: D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000737:chemistry*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000737:chemistry*; D008968:Molecular Conformation
chemical_list: D000242:Cyclic AMP; D006152:Cyclic GMP