Tyrosine/tyrosinate fluorescence at 700 MPa: A pressure unfolding study of chicken ovomucoid at pH 12
| Autor: | Kazuyuki Akasaka, Hiroshi Matsuo, Akihiro Maeno |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
Protein Denaturation
Protein Folding Protein Conformation Chemistry Organic Chemistry Biophysics Partial molar property Hydrogen-Ion Concentration Ovomucin Biochemistry Fluorescence Crystallography Spectrometry Fluorescence Mole Pressure Native state Animals Thermodynamics Tyrosine Intermediate state Fluorescence spectrometer Denaturation (biochemistry) Chickens |
| Zdroj: | Biophysical Chemistry. 183:57-63 |
| ISSN: | 0301-4622 |
| Popis: | The utility of tyrosine/tyrosinate fluorescence for pressure-unfolding studies of Trp-lacking proteins has been explored for the first time, with chicken ovomucoid (OVM) as target. A newly developed fluorescence spectrometer working in the range 0.1-700 MPa is employed for this purpose. At 25 °C at pH 12, all six Tyr residues give tyrosine emission at 306 nm, implying that all five Tyr residues are well buried at pH 12 in the folded OVM, except one giving "half-tyrosinate" emission at 325 nm. Upon increasing pressure, however, a distinct intermediate state, in which domains 1 and 2 are selectively unfolded, appears and increases up to 700 MPa. Extrapolated to 0.1 MPa, this intermediate lies 8.8±2.6 kJ mol(-1) above the native state, characterized with a partial molar volume smaller by -28.9±7.4 ml mol(-1). At 5 °C at 700 MPa, even domain 3 gives a sign of cold denaturation. |
| Databáze: | OpenAIRE |
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