Glass transition of deoxymyoglobin probed by optical absorption spectroscopy.
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.
Kushida
T
T
Department of Physics, Osaka University, Japan.
Ahn
J S
JS
Hirata
K
K
Kurita
A
A
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
D009211:Myoglobin; C055547:deoxymyoglobin; D014867:Water; D005990:Glycerol