TY - JOUR ID - pittir17225 UR - http://d-scholarship-dev.library.pitt.edu/17225/ IS - 7 A1 - Asciutto, EK A1 - Mikhonin, AV A1 - Asher, SA A1 - Madura, JD Y1 - 2008/02/19/ N2 - We demonstrate a calculated ?-helix peptide folding energy landscape which accurately simulates the first experimentally measured ?-helix melting energy landscape. We examine a 21-amino acid, mainly polyalanine peptide and calculate the free energy along the ? Ramachandran angle secondary folding coordinate. The experimental free energy landscape was determined using UV resonance Raman spectroscopy. The relative free energy values are very close as are the equilibrium peptide conformations. We find 2.3 kcal/mol activation barriers between the ?-helix-like and PPII-like basins. We also find that the ?-helix-like conformations are quite defective and the ?-helix-like structure dynamically samples 310-helix and ?-bulges. © 2008 American Chemical Society. JF - Biochemistry VL - 47 SN - 0006-2960 TI - Computational and experimental determination of the ?-helix unfolding reaction coordinate SP - 2046 AV - public EP - 2050 ER -