Thermodynamic molecular switch in sequence‐specific hydrophobic interactions

摘要: This communication will demonstrate the existence of a thermodynamic molecular switch in pairwise, sequence-specific hydrophobic interaction Ile–Ile, Leu–Ile, Val–Leu, or Ala–Leu over temperature range 273–333 K reported by Nemethy and Scheraga 1962. Based on Chun's development Planck–Benzinger methodology, change inherent chemical bond energy at 0 K, ΔH°(T0), is 3.0 kcal mol−1 for 2.4 1.8 1.2 Ala–Leu. The value ΔH°(T0) decreases as length side chain decreases. It clear that strength stability determined packing density chains, with being most stable. At 〈Tm〉, thermal agitation energy, , about five times greater than each case. Additionally, same series, evaluated order, is, highly similar its behavior to other biological systems, except negative Gibbs free minimum 〈Ts〉 occurs considerably higher temperature, 355 compared 300 K. melting also high, 470 343 system. implication well-defined has it origin interactions, which are dependent details structure. In addition four specific dipeptide interactions described, we have shown our unpublished work 32 dipeptides wherein sign ΔCp°(T)reaction leads true reaction, hence, maximum related Keq. Indeed, all interacting systems thus far examined using approach point universality switches. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem,