Fluorescence decay kinetics of the tryptophyl residues of myoglobin: effect of heme ligation and evidence for discrete lifetime components
| Autor: | Arthur G. Szabo, J. M. Ridgeway, K.J. Willis, Bernard Alpert, Michael Zuker |
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| Rok vydání: | 1990 |
| Předmět: |
Protein Conformation
Kinetics Analytical chemistry Fluorescence spectrometry Heme Biochemistry chemistry.chemical_compound Sperm whale Animals Chromatography High Pressure Liquid biology Chemistry Myoglobin Tuna Tryptophan Whales Hydrogen-Ion Concentration biology.organism_classification Fluorescence Crystallography Spectrometry Fluorescence Picosecond |
| Zdroj: | Biochemistry. 29(22) |
| ISSN: | 0006-2960 |
| Popis: | The fluorescence decay kinetics of the tryptophyl residues of sperm whale and yellowfin tuna myoglobin have been determined by using time-correlated single photon counting, with picosecond resolution. Purification by HPLC techniques resulted in the isolation of samples that exclusively displayed picosecond decay kinetics. Lifetimes of 24.4 ps for Trp14 and 122.0 ps for Trp7 were found for oxy sperm whale myoglobin (pH 7), which agree with theoretical predictions [Hochstrasser, R. M., & Negus, D. K. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 4399-4403]. The effects of ligand binding and pH on the decay kinetics were investigated, and the results were shown to be consistent with the known crystal structures. Data for the met form of sperm whale myoglobin were analyzed both in terms of a sum of discrete exponential components and as a continuous gamma distribution of exponential decays. The results were not found to support the existence of multiple, structurally distinct conformation states in myoglobin. |
| Databáze: | OpenAIRE |
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