[IR-spectroscopic and radiographic study of the effect of water vapor on the structure and amorphous state-crystal transition of nucleic acid pyrimidine bases].
Effect of water vapour on sublimated films of nucleic acid pyrimidine bases was studied by IR-spectroscopy and X-ray pattern. It is found that freshly deposited films of uracil present a layered amorphous phase, of isocytosine--an amorphous phase; of cytosine--a crystal one. It is shown that water plays the role of an effective catalyzer providing at room temperature rapid transition of isocytosin from amorphous phase, uracyl from the layered amorphous phase into a crystal one. Under the effect of water sorbed molecules of cytosine changes are observed in the IR-spectrum. The latter are most significant in the region of non-plane deformation variations of NH- and NH2-groups. A mechanism of water effect on structural transformations found by us and the growth of nitrous bases crystals is suggested.
D003460:Crystallization; D003596:Cytosine; D013055:Spectrophotometry, Infrared; D014498:Uracil; D014867:Water; D014961:X-Ray Diffraction
D014867:Water; D014498:Uracil; D003596:Cytosine
IK-spektroskopicheskoe i rentgenograficheskoe issledovanie vliianiia parov vody na strukturu i perikhod amorfnoe sostoianie-kristall pirimidinovykh osnovaniĭ nukleinovykh kislot