STUDY OF THE PHASE-SPACE STRUCTURE FOR A 2-DEGREES OF FREEDOM MODEL OF A SYMMETRICAL GLYCOSIDIC LINKAGE

Classical dynamics calculations have been carried out on a two-degrees of freedom model Hamiltonian representing the symmetric glycosidic li nkage of beta,beta-trehalose. The Hamiltonian depends on coordinates P hi and Phi' and their conjugate momenta, where Phi and Phi' are the to rsional angles M-C-1-O-1-C-1' and M'-C-1'-O-1-C-1 defined by the carbo n and oxygen atoms of the glycosidic linkage and by pseudo-atoms M and M' representing the effect of the pyranose rings. We have employed a simplified potential function reproducing the major features of molecu lar mechanics results in the literature. All relevant initial conditio ns for energy values ranging up to the energy of rotation have been tr ied. Results have been examined by considering the plots Phi(t) and Ph i'(t), the trajectories in the configuration space (Phi,Phi') for sing le initial conditions, and the Poincare Surfaces of Sections, which de scribe the behavior of the system in the phase space, for all initial conditions at fixed energy. (C) 1997 Elsevier Science Ltd.