Berlin 2012 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
BP: Fachverband Biologische Physik
BP 15: Proteins II
BP 15.2: Vortrag
Mittwoch, 28. März 2012, 15:30–15:45, H 1058
Probing the Ca2+ - switch of the neuronal Ca2+ sensor GCAP2 by time-resolved fluorescence spectroscopy — •Heiko Kollmann1, Simon F. Becker1, Javid Shirdel1, Anna Osterndorp2, Christoph Lienau1, and Karl-Wilhelm Koch2 — 1Ultraschnelle Nano-Optik, Institut für Physik, Fakultät V, Universität Oldenburg, 26111 Oldenburg, Deutschland — 2Biochemie, Institut für Biologie und Umweltwissenschaften, Fakultät V, Universität Oldenburg, 26111 Oldenburg, Deutschland
We report fluorescence lifetime and rotational anisotropy measurements of the fluorescence dye Alexa647 attached to the guanylate cyclase-activating protein 2 (GCAP2), an intracellular myristoylated calcium sensor protein operating in photoreceptor cells. By linking the dye to different protein regions critical for monitoring calcium-induced conformational changes, we could measure fluorescence lifetimes and rotational correlation times as a function of myristoylation, calcium and position of the attached dye, while keeping the GCAP2 protein operational. We observe distinct site-specific variations in the fluorescence dynamics when externally changing the protein conformation. A key feature of the dynamics of the protein-dye complex is the up- and down-movement of an α-helix that is situated between the two specific linking positions. Operation of this piston-like movement is triggered by the intracellular messenger calcium.