Parts | Days | Selection | Search | Downloads | Help
Q: Fachverband Quantenoptik und Photonik
Q 65: Laseranwendungen: Lebenswissenschaften
Q 65.3: Talk
Friday, March 6, 2009, 14:30–14:45, VMP 8 HS
Photodynamics of blue-light-regulated phosphodiesterase BlrP1 protein from Klebsiella pneumoniae — •Amit Tyagi1, Alfons Penzkofer1, Julia Griese2, Ilme Schlichting2, Natalia V. Kirienko3, and Mark Gomelsky3 — 1Institut II - Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, D-93053 Regensburg, Germany — 2Max-Planck-Institut für medizinische Forschung, Abteilung Biomolekulare Mechanismen, Jahnstrasse 29, D-69120 Heidelberg, Germany — 3Department of Molecular Biology, University of Wyoming, Laramie, Wyoming 82071, USA
The blue light-regulated phosphodiesterase BlrP1 protein from the enteric bacterium Klebsiella pneumoniae consists of a BLUF (sensor of blue light using FAD) and an EAL (E = Glu, A = Ala, L = Leu) domain. The full-length protein, BlrP1, and its BLUF domain, BlrP1_BLUF, are characterized by optical absorption and emission spectroscopy. The cofactor FAD in its oxidized redox state (FADox) is brought from the dark-adapted receptor state to the 10 nm red-shifted putative signalling state by violet light exposure. The recovery to the receptor state occurs with a time constant of about 1 min. The quantum yield of signalling-state formation is about 0.17 for BlrP1_BLUF and about 0.08 for BlrP1. The fluorescence efficiency of the FADox cofactor is small due to photo-induced reductive electron transfer. Prolonged light exposure converts FADox in the signalling state to the fully reduced hydroquinone form FADredH− and causes low-efficient chromophore release with subsequent photo-degradation.