Aggregation transition in larger heteropolymer systems

Yet utilizing that with Eq. (11.14), the canonical distribution hcan(E) = f dT HcmiE, F T) at Fagg (shown in Fig. 11.7) is ham(,E)g E) exp(—E /ArnFagg), the surface entropy can be written in the simple and computationally convenient form [260]  

A similar expression is valid for the coexistence of premolten and fragmented states at Fpre- The corresponding canonical distribution is also shown in Fig. 11.7. Thus, the surface entropy (in units of b) of the aggregation transition in this example is 2.48 and for 

Although the formation of compact hydrophobic cores is more complex in larger compounds of our exemplified sequence FI, the aggregation transition is little influenced by this. This is nicely seen in Figs. 11.8(a) and 11.8(b), where the temperature dependence of the canonical expectation values of F and E, as well as for their fluctuations, are shown for the 3xFl system. For comparison, results for the 4xFI system are plotted into the same figures.  

As it has already been discussed for the 2xFl system, there are also for the larger systems no obvious signals for separate aggregation and hydrophobic-core formation 

For homogeneous multiple-chain systems, two variants of thermodynamic limits are of particular interest (i) M oo, while = const, (ii) oo with M= const both limits considered for constant polymer density. Since for proteins the sequence of amino acids is fixed, in this case only (i) is relevant and it is possible to perform a scaling analysis for multiple-peptide systems in this limit. A particularly interesting question is to what extent remnants of the finite-system effects survive in the limit of an infinite number of chains, dependent of the peptide density. Since we have focused our study on the precise analysis of systems of few peptides for all energies and temperatures, it is computationally 

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