Berlin 2005 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 29: POSTER: Polymer physics

CPP 29.59: Poster

Dienstag, 8. März 2005, 16:30–18:30, Poster TU D

Globular Structures of Helix-Coil Copolymers: A SCFT Treatment — •Christian Nowak, Vakhtang Rostiashvili, and Thomas Vilgis — Max Planck Institut für Polymerforschung, Ackermannweg 10, 55128 Mainz

A general self-consistent field theory to describe the conformational behavior of a single helix-coil copolymer is constructed. The helices are modeled by stiff rods which are connected to flexible, coil-like spacer chains. The short ranged interactions between the individual segments are modeled by Flory-Huggins type parameters. In addition, an orientation dependent Maier-Saupe like interaction between the helices is introduced to account for ordering of the helices along the copolymer.

The use of a grand canonical formulation becomes necessary since each segment may undergo a microscopic transition between helix state and coil state. Hence the distribution of helix lengths is not fixed but determined by equilibrium conditions.

Due to the competing entropic and energetic contributions the model shows a transition between open structures and globular states which in turn affects the formation of helices. Therefore the theory can be used as a rather general model to describe the hydrophobic collapse and formation of helix bundles in proteins.