Amide-to-E-olefin versus amide-to-ester backbone H-bond perturbations: Evaluating the O-O repulsion for extracting H-bond energies.
Both amide-to-ester and amide-to-E-olefin backbone amide mutation methods were employed to perturb the same H-bond (formed by the NH of F23 and the CO of R14) in the Pin WW domain. Comparison of the thermodynamic folding energies of the ester mutant and the E-olefin mutant, accounting for the transfer free energy differences measured on relevant model compounds, yielded an estimated value of 0.3 kcal/mol for the O-O repulsion term (DeltaGO-Orep) in a beta-sheet context. The value of DeltaGO-Orep enabled us to calculate the intrinsic F23-R14 H-bond free energy to be 1.3 kcal/mol.
Fu
Yanwen
Y
Department of Chemistry and The Skaggs Institute of Chemical Biology, The Scripps Research Institute, BCC 506, La Jolla, California 92037, USA.
Gao
Jianmin
J
Bieschke
Jan
J
Dendle
Maria A
MA
Kelly
Jeffery W
JW
D000475:Alkenes / Q000737:chemistry*; D000577:Amides / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry*; D013816:Thermodynamics
D000475:Alkenes; D000577:Amides; D004952:Esters; D010100:Oxygen