title: Toward the physical basis of thermophilic proteins: linking of enriched polar interactions and reduced heat capacity of unfolding.
abstract: The enrichment of salt bridges and hydrogen bonding in thermophilic proteins has long been recognized. Another tendency, featuring lower heat capacity of unfolding (DeltaC(p)) than found in mesophilic proteins, is emerging from the recent literature. Here we present a simple electrostatic model to illustrate that formation of a salt-bridge or hydrogen-bonding network around an ionized group in the folded state leads to increased folding stability and decreased DeltaC(p). We thus suggest that the reduced DeltaC(p) of thermophilic proteins could partly be attributed to enriched polar interactions. A reduced DeltaC(p) might serve as an indicator for the contribution of polar interactions to folding stability.
authors.affiliation: Institute of Molecular Biophysics and Department of Physics, Florida State University, Tallahassee, FL 32306, USA. zhou@sb.fsu.edu
authors.forename: Huan-Xiang
authors.initials: HX
authors.lastname: Zhou
mesh_terms: D001105:Archaea / Q000737:chemistry / Q000378:metabolism; D019843:Archaeal Proteins / Q000737:chemistry* / Q000648:ultrastructure; D003198:Computer Simulation; D004563:Electrochemistry / Q000379:methods; D004735:Energy Transfer; D006358:Hot Temperature; D006860:Hydrogen Bonding; D046911:Macromolecular Substances; D008956:Models, Chemical; D008958:Models, Molecular; D011487:Protein Conformation; D011489:Protein Denaturation; D017510:Protein Folding; D011506:Proteins / Q000737:chemistry*; D016914:Ribonuclease H / Q000737:chemistry; D012492:Salts / Q000737:chemistry; D012997:Solvents / Q000737:chemistry; D055672:Static Electricity; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D019843:Archaeal Proteins; D046911:Macromolecular Substances; D011506:Proteins; D012492:Salts; D012997:Solvents; D014867:Water; D016914:Ribonuclease H