Hydrophobic-polar off-lattice heteropolymers

A manifest off-lattice generalization of the HP model is the AB model (1.13), where the hydrophobic monomers are labeled A and the polar or hydrophilic ones, 5 [ 14]. The contact interaction is replaced by a distance-dependent Leimard-Jones type of potential accounting for short-range excluded volume repulsion and long-range interaction, the latter being attractive for AA and BB pairs and repulsive for AB pairs of monomers. An additional 

Generic tertiary foiding properties of proteins on mesoscopic scales 

We will now investigate thermodynamic properties of AB heteropolymers and compare their folding properties for different secpiences. For this purpose, we consider the six exemplified heteropolymers with 20 monomers [187] listed in Table 8.1. The hydrophobicity (= A monomers in the sequence) is identical (=14) for the first four sequences 20.1-20.4, while sequences 20.5 and 20,6 possess only 10 hydrophobic residues. Sequence 20.7 is the homopolymer A20 consisting of hydrophobic residues only. 

The sequences considered here are very short and the native fold contains a single hydrophobic core. Interpreting the curves for the specific heats in Fig. 8.5 in terms of conformational transitions, we conclude that the heteropolymers tend to form, within the temperature region T intermediate states (often also called traps) comparable with globules in the collapsed phase of polymers. For sequences 20.5 and, in particular, 20.6 the smaller number of hydrophobic monomers causes a much sharper 

Multicanonical histogram hmua (f) and logarithm of the density of states g E) tor sequence 20.1. From [47]. 

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