Berlin 2015 – scientific programme

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BP: Fachverband Biologische Physik

BP 52: Protein structure and dynamics II

BP 52.3: Talk

Friday, March 20, 2015, 10:15–10:30, H 1028

Photo-dynamics of photo-activated adenylyl cyclase NgPAC3 from the amoeboflagellate Naegleria gruberi NEG-M strain — •Alfons Penzkofer¹, Meenakshi Tanwar², Sinddu Kandoth Veetil², Suneel Kateriya², Manuela Stierl³, and Peter Hegemann³ — ¹Fakultät für Physik, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany — ²Department of Biochemistry, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India — ³Institut für Biologie/Experimentelle Biophysik, Humboldt Universität zu Berlin, Invalidenstraße 42, D-10115 Berlin, Germany

The absorption and emission spectroscopic behavior of the photo-activated adenylyl cyclase NgPAC3 from the amoeboflagellate Naegleria gruberi NEG-M strain was studied [1]. The flavin cofactor was found to be partly fully oxidized and partly fully reduced. The typical BLUF domain (BLUF = Blue Light sensor Using Flavin) fully oxidized flavin absorption photo-cycle dynamics with about 14 nm flavin absorption red-shift in the signaling state was observed. The quantum efficiency of signaling state formation was determined to be φ_s = 0.66±0.03. A bi-exponential signaling state recovery to the dark-adapted receptor state was observed with the time constants τ_rec,f = 275 s (fraction 0.29) and τ_rec,sl = 45 min (fraction 0.71). The thermal irreversible protein unfolding was studied and a protein melting temperature of ϑ_m ≈ 50 ^∘C was found. NgPAC3 showed light-gated adenylate cyclase activity upon illumination with blue light.

[1] A.Penzkofer et al., J.Photochem.Photobiol.A:Chem. 287(2014)19.