MONOMORPHISM OF CYTIDINE (CYD) VS. POLYMORPHISM OF 2'DEOXYCYTIDINE (DCYD) - STRUCTURAL AND FUNCTIONAL CONSEQUENCES

It has been found that 2'deoxycytidine (dCyd) crystallizes in differen t forms, denoted dCyd A, dCyd B and dCyd C . H2O.0. In the crystal lat tice of the newly discovered form dCydC . H2O there is a crystalline w ater molecule present. The monohydrate of dCydC, under suitable condit ions (RT, over P2O5, 48 h), undergoes transformation into the fully de hydrated form-dCydC anhydro. The whole process of de- and re-hydratati on has been observed by FTIR-PAS spectroscopy. The nature of the diffe rences and similarities between structural and functional properties o f crystalline forms of 2'dCyd and Cyd molecules has been discussed. (C ) 1997 Elsevier Science B.V.