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Zohre Eskandari Alughare

Visit: Two Months

Zohre Eskandari Alughare from the group of Professor Dr. Michel Orrit, Leiden University will visit Prof. Dr. Don C. Lamb, Ludwig-Maximilians-Universität München

Zohre Eskandari Alughare
Zohre Eskandari Alughare

Kinetics of CO rebinding to single Myoglobin molecules using Förster Resonance Energy Transfer (FRET) at cryogenic temperatures

Myoglobin plays a crucial role as an oxygen storage protein in muscle tissue, and the binding of small molecules such as O2, CO, NO, H2S to the heme of Myoglobin has been studied extensively. Low-temperature experiments by Frauenfelder and coworkers in the 1970s demonstrated that, at cryogenic temperatures, rebinding of CO to myoglobin's heme cofactor after flash photolysis shows a strongly stretched exponential behavior, that is not observed at room temperature. This project aims at confirming on individual molecules, while the ensemble experiments done by Frauenfelder and colleagues more than 30 years ago. Thereby, we hope to get insight into the amount of dynamical heterogeneity in small proteins. The rebinding kinetics of CO can be measured precisely through the quenching of a fluorescent dye attached to the myoglobin using Förster Resonance Energy Transfer (FRET). To observe clear fluorescence quenching, myoglobin needs to be labeled efficiently and specifically with a suitable dye at a suitable position. Our last experiment with our collaborator Prof. Don Lamb at LMU demonstrated that labeling at close position to heme is crucial. Therefore, The next step is the labeling at optimal position with proper dye using two variants mutation of myoglobin and lifetime measurement to obtain  FRET efficiency and CO rebinding kinetic parameters.