AI Article Synopsis
- The study examines how the average fluorescence lifetime (τav) of tryptophanyls in the photosynthetic reaction center of purple bacteria Rb. sphaeroides varies when frozen in the dark versus when exposed to light.
- This difference in τav disappears when the sample is heated above 250 K.
- Computer simulations identified vibrational modes in the tryptophan molecule, suggesting that changes in these modes, influenced by the local environment during light activation, might explain the variations in fluorescence lifetime.
Article Abstract
The differences in the average fluorescence lifetime (τav) of tryptophanyls in photosynthetic reaction center (RC) of the purple bacteria Rb. sphaeroides frozen to 80 K in the dark or on the actinic light was found. This difference disappeared during subsequent heating at the temperatures above 250 K. The computer-based calculation of vibration spectra of the tryptophan molecule was performed. As a result, the normal vibrational modes associated with deformational vibrations of the aromatic ring of the tryptophan molecule were found. These deformational vibrations may be active during the nonradiative transition of the molecule from the excited to the ground state. We assume that the differences in τav may be associated with the change in the activity of these vibration modes due to local variations in the microenvironment of tryptophanyls during the light activation.
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| http://dx.doi.org/10.1134/S1607672916020083 | DOI Listing |
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