α-Nucleosides in biological systems

Electrostatic properties of β-cytidine and cytosine monohydrate from Bragg diffraction

“…The results agree within experimental error with a recent room-temperature redetermination based on diffractometer data (Ward, 1993). Other related crystal structures which have been determined at atomic resolution include ot-cytidine (Post, Birnbaum, Huber & Shugar, 1977), in which the ribose has the ot-anomeric configuration, 1-fl-I:)-arabinosylcytosine (Tougard & Lefebvre-Soubeyran, 1974), cytosine (Barker & Marsh, 1964;McClure & Craven, 1973) and cytosine monohydrate by X-ray diffraction (Jeffrey & Kinoshita, 1963;McClure & Craven, 1973) and neutron diffraction at 82 K (Weber, Craven & McMullan, 1980). Many crystal complexes involving G--C base pairs have been studied, the most notable being sodium guanylyl-3',5'-cytidine nonahydrate (Rosenberg, Seeman, Day & Rich, 1976), because this structure first showed minihelical RNA at atomic resolution.…”

Saturation molalities and standard molar enthalpies of solution of cytidine(cr), hypoxanthine(cr), thymidine(cr), thymine(cr), uridine(cr), and xanthine(cr) in H2O(l)

“…a Two crystalline forms of cytidine have been reported [19] in the literature, an a and b form. The unit cell parameters given above show that bcytidine(cr) was used in this study.…”

β-Cytidine, C9H13N3O5

“…As the previous studies used data collection and computational methods that are no longer considered adequate, and as no other structure report of ~-cytidine was discovered, it was decided to report the present structure. The crystal structure determination of a-cytidine, which used diffractometer data and led to an R factor of 0.033, was reported by Post, Birnbaum, Huber & Shugar (1977).…”

“…The description of the molecular structure by Furberg et al (1965) applies to the present structure, if one allows for the change in atom numbering to be consistent with the conventions of Post et al (1977) and Chemical Abstracts, and also for the coordinate-origin translation of 1 1 ~ The average difference between the C--C, (1977) average only 0.007 A; bond-angle differences are large (average 1.5 °) and are likely to be the result of the different molecular configurations and crystal packing.…”