CPSP-tools – Exact and complete algorithms for high-throughput 3D lattice protein studies

<p>Abstract</p> <p>Background</p> <p>The principles of protein folding and evolution pose problems of very high inherent complexity. Often these problems are tackled using simplified protein models, e.g. lattice proteins. The CPSP-tools package provides programs to solve exactly and completely the problems typical of studies using 3D lattice protein models. Among the tasks addressed are the prediction of (all) globally optimal and/or suboptimal structures as well as sequence design and neutral network exploration.</p> <p>Results</p> <p>In contrast to stochastic approaches, which are not capable of answering many fundamental questions, our methods are based on fast, non-heuristic techniques. The resulting tools are designed for high-throughput studies of 3D-lattice proteins utilising the Hydrophobic-Polar (HP) model. The source bundle is freely available <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>.</p> <p>Conclusion</p> <p>The CPSP-tools package is the first set of exact and complete methods for extensive, high-throughput studies of non-restricted 3D-lattice protein models. In particular, our package deals with cubic and face centered cubic (FCC) lattices.</p

The protein sequence design problem in canonical model on 2D and 3D lattices

Abstract. In this paper we investigate the protein sequence design (PSD) problem (also known as the inverse protein folding problem) under the Canonical model 4 on 2D and 3D lattices [12, 25]. The Canonical model is specified by (i) a geometric representation of a target protein structure with amino acid residues via its contact graph, (ii) a binary folding code in which the amino acids are classified as hydrophobic (H) or polar (P), (iii) an energy function Φ defined in terms of the target structure that should favor sequences with a dense hydrophobic core and penalize those with many solvent-exposed hydrophobic residues (in the Canonical model, the energy function Φ gives an H-H residue contact in the contact graph a value of −1 and all other contacts a value of 0), and (iv) to prevent the solution from being a biologically meaningless all H sequence, the number of H residues in the sequence S is limited by fixing an upper bound λ on the ratio between H and P amino acids. The sequence S is designed by specifying which residues are H and which one