Competition for hydrogen bond formation in the helix-coil transition and protein folding

Abstract

The problem of the helix-coil transition of biopolymers in explicit solvents, like water, with the ability for hydrogen bonding with solvent is addressed analytically using a suitably modified version of the Generalized Model of Polypeptide Chains. Besides the regular helix-coil transition, an additional coil-helix or reentrant transition is also found at lower temperatures. The reentrant transition arises due to competition between polymer-polymer and polymer-water hydrogen bonds. The balance between the two types of hydrogen bonding can be shifted to either direction through changes not only in temperature, but also by pressure, mechanical force, osmotic stress or other external influences. Both polypeptides and polynucleotides are considered within a unified formalism. Our approach provides an explanation of the experimental difficulty of observing the reentrant transition with pressure; and underscores the advantage of pulling experiments for studies of DNA. Results are discussed and compared with those reported in a number of recent publications with which a significant level of agreement is obtained.

21 pages, 3 figures, submitted to Phys Rev E

References in corpus (6)

• An Ising-Like model for protein mechanical unfolding
• Denaturation transition of stretched DNA
• Microscopic formulation of the Zimm-Bragg model for the helix-coil transition
• Liquid polymorphism, order-disorder transitions and anomalous behavior: a Monte Carlo study of the Bell-Lavis model for water
• Melting of persistent double-stranded polymers
• Effect of external stress on the thermal melting of DNA

Cited by in corpus (8)

• Contribution of Water to Pressure and Cold Denaturation of Proteins
• Osmotic pressure induced coupling between cooperativity and stability of a helix-coil transition
• A unified description of solvent effects in the helix-coil transition
• Exact solution of a classical short-range spin model with a phase transition in one dimension: the Potts model with invisible states
• Solvent Effects in the Helix-Coil Transition Model can explain the Unusual Biophysics of Intrinsically Disordered Proteins
• Potts Model with Invisible States: A Review
• Classical phase transitions in a one-dimensional short-range spin model induced by entropy depletion or complex fields
• Ising model with invisible states on scale-free networks