Paper of the Month: September Edition
Circular dichroism is an established biophysical tool for the investigation of charge transfer transitions in metal-protein complexes. However, it can still be challenging to interpret the intricate profiles of UV/Vis CD spectra. In this study, the origin of the UV/Vis CD profile of gloeobacter rhodopsin was elucidated. This protein is a light-activated proton pump that contains a retinal chromophore as well as the carotenoid salinixanthin. Comprehensive CD studies including substitution of retinal by synthetic analogues revealed that the observed spectral bands originate from excitonic interaction between the two chromophores and induced chirality of salinixanthin upon protein binding. Together with additional findings, this study contributes to a better understanding of the CD profiles observed in the UV/Vis range for rhodopsins and other proteins containing co-factors absorbing in the visible range.
Jana, Jung, and Sheves. 2020. “The Chirality Origin of Retinal-Carotenoid Complex in Gloeobacter Rhodopsin: A Temperature-Dependent Excitonic Coupling.” Scientific Reports 10: 13992.
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