title: [Conformational transitions in adsorbed macromolecules with secondary structure].
abstract: An analytical theory is presented taking into account the effects of the flat adsorbing surface on the equilibrium properties of the long single-stranded macromolecule possessing a secondary structure. Change of the secondary structure is described in terms of Zimm--Bragg theory; adsorbtion properties are calculated for the lattice model without taking into account the 3-dimensional interactions. It is shown that the presence of the adsorbing surface sharpens helix-coil transition, displacing it towards the lower constants of equilibrium (s). A relation of the critical energy of adsorbtion (--epsilonkappa) on s is obtained at different values of the cooperativity factor sigma. This relationship represents a phase diagram of the system. Various sections of this phase diagram corresponding to different dependence of s and --epsilon on the external factors are considered. It is shown that the process of adsorbtion may occur in different manners: either cooperatively or by the phase transition of type II with jumps in one or in three points.
mesh_terms: D007700:Kinetics; D046911:Macromolecular Substances; D008433:Mathematics; D008954:Models, Biological; D008968:Molecular Conformation
chemical_list: D046911:Macromolecular Substances
vernacular_title: Konformatsionnye perekhody v adsorbirovannykh makromolekulakh s vtorichnoĭ strukturoĭ.