Finite size effects on calorimetric cooperativity of two-state proteins
نویسندگان
چکیده
Finite size effects on the calorimetric cooperatity of the folding-unfolding transition in two-state proteins are considered using the Go lattice models with and without side chains. We show that for models without side chains a dimensionless measure of calorimetric cooperativity κ2 defined as the ratio of the van’t Hoff to calorimetric enthalpy does not depend on the number of amino acids N . The average value κ2 ≈ 3
منابع مشابه
Polymer principles of protein calorimetric two-state cooperativity.
The experimental calorimetric two-state criterion requires the van't Hoff enthalpy DeltaH(vH) around the folding/unfolding transition midpoint to be equal or very close to the calorimetric enthalpy DeltaH(cal) of the entire transition. We use an analytical model with experimental parameters from chymotrypsin inhibitor 2 to elucidate the relationship among several different van't Hoff enthalpies...
متن کاملFinite size effects on thermal denaturation of globular proteins.
Finite size effects on the cooperative thermal denaturation of proteins are considered. A dimensionless measure of cooperativity, Omegac, scales as Nzeta, where N is the number of amino acids. Surprisingly, we find that zeta is universal with zeta=1+gamma, where the exponent gamma characterizes the divergence of the susceptibility for a self-avoiding walk. Our lattice model simulations and expe...
متن کاملEnergetics of Protein Thermodynamic Cooperativity: Contributions of Local and Nonlocal Interactions
The respective roles of local and nonlocal interactions in the thermodynamic cooperativity of proteins are investigated using continuum (off-lattice) native-centric Gō-like models with a coarse-grained Ca chain representation. We study a series of models in which the (local) bondand torsion-angle terms have different strengths relative to the (nonlocal) pairwise contact energy terms. Conformati...
متن کاملTowards a consistent modeling of protein thermodynamic and kinetic cooperativity: how applicable is the transition state picture to folding and unfolding?
To what extent do general features of folding/unfolding kinetics of small globular proteins follow from their thermodynamic properties? To address this question, we investigate a new simplified protein chain model that embodies a cooperative interplay between local conformational preferences and hydrophobic burial. The present four-helix-bundle 55mer model exhibits protein-like calorimetric two...
متن کاملCooperativity in biological systems
Living organisms can sense and respond to external and internal stimuli. Response isdemonstrated in many forms including modulation of gene expression profiles, motility,secretion, cell death, etc. Nevertheless, all forms share a basic property: they depend on sensingsmall changes in the concentration of an effector molecule or subtle conformational changes ina protein and invoking the appropri...
متن کامل