title: Glass transition of deoxymyoglobin probed by optical absorption spectroscopy.
abstract: We have measured the absorption spectrum of horse deoxymyoglobin in glycerol-water mixture around 430 nm in the 130 - 320 K temperature range. The observed asymmetric spectral shape of the Soret band was analyzed using a configuration-coordinate model. The results support the idea that myoglobin is liquid-like at physiological temperatures, but is glass-like below about 250 K. The equilibrium position of the iron atom in the heme group in the electronic excited state was estimated from the determined parameter values.
authors.affiliation: Department of Physics, Osaka University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kushida
authors.forename: J S
authors.initials: JS
authors.lastname: Ahn
authors.forename: K
authors.initials: K
authors.lastname: Hirata
authors.forename: A
authors.initials: A
authors.lastname: Kurita
mesh_terms: D000818:Animals; D005615:Freezing; D005898:Glass; D005990:Glycerol; D009211:Myoglobin / Q000031:analogs & derivatives*; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D013696:Temperature; D013816:Thermodynamics; D014867:Water
chemical_list: D009211:Myoglobin; C055547:deoxymyoglobin; D014867:Water; D005990:Glycerol