Observation of Robust Energy Transfer in the Photosynthetic Protein Allophycocyanin Using Single-Molecule Pump–probe Spectroscopy was published in January 2022.
A paper authored by Raymundo Moya, Audrey C. Norris, Toru Kondo, and Professor Gabriela S. Schlau-Cohen was published in Nature Chemistry on January 6, 2022.
Observation of Robust Energy Transfer in the Photosynthetic Protein Allophycocyanin Using Single-Molecule Pump–probe Spectroscopy
Raymundo Moya, Audrey C. Norris, Toru Kondo, & Gabriela S. Schlau-Cohen
Published 6 January 2022
Photosynthetic organisms convert sunlight to electricity with near unity quantum efficiency. Absorbed photoenergy transfers through a network of chromophores positioned within protein scaffolds, which fluctuate due to thermal motion. The resultant variation in the individual energy transfer steps has not yet been measured, and so how the efficiency is robust to this variation has not been determined. Here, we describe single-molecule pump–probe spectroscopy with facile spectral tuning and its application to the ultrafast dynamics of single allophycocyanin, a light-harvesting protein from cyanobacteria. We disentangled the energy transfer and energetic relaxation from nuclear motion using the spectral dependence of the dynamics. We observed an asymmetric distribution of timescales for energy transfer and a slower and more heterogeneous distribution of timescales for energetic relaxation, which was due to the impact of the protein environment. Collectively, these results suggest that energy transfer is robust to protein fluctuations, a prerequisite for efficient light harvesting.
The Schlau-Cohen Group is inherently multidisciplinary, combining tools from chemistry, optics, biology, and microscopy to develop new approaches to probe dynamics.