title: Free energy self-averaging in protein-sized random heteropolymers.
abstract: Current theories of heteropolymers are inherently macroscopic, but are applied to mesoscopic proteins. To compute the free energy over sequences, one assumes self-averaging--a property established only in the macroscopic limit. By enumerating the states and energies of compact 18, 27, and 36mers on a lattice with an ensemble of random sequences, we test the self-averaging approximation. We find that fluctuations in the free energy between sequences are weak, and that self-averaging is valid at the scale of real proteins. The results validate sequence design methods which exponentially speed up computational design and simplify experimental realizations.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J
authors.initials: J
authors.lastname: Chuang
authors.forename: A Y
authors.initials: AY
authors.lastname: Grosberg
authors.forename: M
authors.initials: M
authors.lastname: Kardar
mesh_terms: D008956:Models, Chemical; D011487:Protein Conformation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics
chemical_list: D011506:Proteins