| Autor: |
van Oort B; Laboratory of Biophysics, Wageningen University, The Netherlands., Eremeeva EV, Koehorst RB, Laptenok SP, van Amerongen H, van Berkel WJ, Malikova NP, Markova SV, Vysotski ES, Visser AJ, Lee J |
| Jazyk: |
angličtina |
| Zdroj: |
Biochemistry [Biochemistry] 2009 Nov 10; Vol. 48 (44), pp. 10486-91. |
| DOI: |
10.1021/bi901436m |
| Abstrakt: |
Addition of calcium ions to the Ca(2+)-regulated photoproteins, such as aequorin and obelin, produces a blue bioluminescence originating from a fluorescence transition of the protein-bound product, coelenteramide. The kinetics of several transient fluorescent species of the bound coelenteramide is resolved after picosecond-laser excitation and streak camera detection. The initially formed spectral distributions at picosecond-times are broad, evidently comprised of two contributions, one at higher energy (approximately 25,000 cm(-1)) assigned as from the Ca(2+)-discharged photoprotein-bound coelenteramide in its neutral state. This component decays much more rapidly (t(1/2) approximately 2 ps) in the case of the Ca(2+)-discharged obelin than aequorin (t(1/2) approximately 30 ps). The second component at lower energy shows several intermediates in the 150-500 ps times, with a final species having spectral maxima 19 400 cm(-1), bound to Ca(2+)-discharged obelin, and 21 300 cm(-1), bound to Ca(2+)-discharged aequorin, and both have a fluorescence decay lifetime of 4 ns. It is proposed that the rapid kinetics of these fluorescence transients on the picosecond time scale, correspond to times for relaxation of the protein structural environment of the binding cavity. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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