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MO: Fachverband Molekülphysik
MO 16: Femtosecond Spectroscopy II
MO 16.8: Vortrag
Donnerstag, 12. März 2020, 15:45–16:00, f102
Point-Mutation (W76F) in Anabaena Sensory Rhodopsin Investigated by Femtosecond Time-Resolved Spectroscopy — •Oskar Kefer1, Rei Abe-Yoshizumi2, Nicoló Alagna1, Hideki Kandori2, and Tiago Buckup1 — 1Physikalisch-Chemisches Institut, Ruprecht-Karls Universitat Heidelberg, Germany — 2OptoBioTechnology Research Center, Nagoya Institute of Technology, Japan
ASR is a microbial retinal protein (MRP) that contains two isomeric chromophores, which can undergo ultrafast photo-isomerization. Point mutation inside the retinal pocket of anabaena sensory rhodopsin (ASR) is an efficient way to investigate the structural changes during the isomerization of the retinal protonated Schiff-base (RPSB). Pre-distortion of the conjugated π-framework of retinal is believed to be a major factor in the acceleration of the isomerization rate. This pre-distortion is observable in the ground-state vibrational Raman activity of the C14-H-out-of-plane (HOOP) mode (around 800cm−1) and present in some ASR mutants with accelerated dynamics. Coherent time-resolved vibrational and femtosecond pump-probe experiments were used to investigate the structural changes of RPSB in a W76F point-mutated ASR derivative. By comparing resonant DFWM-measurements with non-resonant DFWM-measurements the vibrational modes of the excited-state manifold can be obtained. This mutant shows no significant HOOP-mode activity in the ground state vibrational Raman spectrum compared to wild-type ASR, further corroborating the role of pre-distortion in the Retinal isomerization.