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Optical spectroscopic differentiation of various equilibrium denatured states of horse cytochrome c
Author(s) -
Xu Qi,
Keiderling Timothy A.
Publication year - 2004
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20011
Subject(s) - chemistry , cytochrome c , heme , fourier transform infrared spectroscopy , circular dichroism , hemeprotein , denaturation (fissile materials) , molten globule , vibrational circular dichroism , infrared , cytochrome , crystallography , infrared spectroscopy , photochemistry , analytical chemistry (journal) , organic chemistry , nuclear chemistry , biochemistry , physics , quantum mechanics , optics , mitochondrion , enzyme
Thermal unfolding of cytochrome c (cyt c) from several states has been studied using equilibrium spectroscopic techniques. CD in the uv, vibrational circular dichroism, infrared, and uv‐vis absorption spectra measured at various temperatures, pHs, salt concentrations, and GuHCl concentrations are used to show the conformational as well as heme structural differences between native and various denatured states. The difference in thermal denaturation behaviors of cyt c starting from acid denatured, molten globule (MG), and the A and native states are explored. Different final high temperature states were observed for cytochrome c unfolding from four different initial states (native, MG, A, and acid denatured state) by electronic CD, Fourier transform infrared (FTIR), and vibrational CD (VCD). Consistent with this, different thermal unfolding pathways for the MG and A states are suggested by the FTIR and VCD data for this process. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004