1-Octadecylcytosine (C18Cyt) with guanine nucleoside pairs develop spiral shaped domains of both handedness in the monolayers composed of pure enantiomer. Globally optimized structures of the pair with different puckering of oxy and deoxy pairs are studied using hybrid quantum mechanical-molecular mechanical theory and the mutual azimuthal orientations for two molecular pairs are investigated. Both left-handedness and right-handedness of domain curvature for oxy as well as deoxy pairs are predicted by theoretical calculations in nice agreement with experiment. The present study definitively correlates the molecular chirality of sugar ring with the domain morphology of nucleic acid mimetic systems. © 2005 Elsevier B.V. All rights reserved.