Carotenoid responds to excess energy dissipation in the LH2 complex from Rhodoblastus acidophilus

Carotenoid-Mediated Long-Range Energy Transfer in the Light Harvesting–Reaction Center Complex from Photosynthetic Bacterium Roseiflexus castenholzii

“…Taken together, the dip-hump feature of wt - LH–RC induced by NIR photoexcitation is most likely the vibronic GSB of Car­(S 2 ← S 0 ) absorption. Similar nonnegative Car GSB signals had also been observed for rhodopin glucoside containing LH2 complex from Rhodoblastus acidophilus under B800 Q y -excitation, which was ascribed to electrochromic shift …”

“…Similar nonnegative Car GSB signals had also been observed for rhodopin glucoside containing LH2 complex from Rhodoblastus acidophilus under B800 Q y -excitation, which was ascribed to electrochromic shift. 47 Origin of Car Dip-Hump Signal Observed for wt-LH− RC. To verify the origin of the dip-hump signal of Car observed for wt-LH−RC, we subtracted the spectral transients of m-LH−RC from those of wt-LH−RC at the same delay time, and the resulting ΔΔOD spectra are presented in Figure 4C,D.…”

Reinvestigation on primary processes of PSII-dimer from Thermosynechococcus vulcanus by femtosecond pump-probe spectroscopy

“…Thus, carotenoids safely quench triplet Chl a to inhibit yields of singlet oxygen as a photoprotection function (Frank and Cogdell 1996). The triplet-triplet energy transfer between Cars and (B)Chls takes place in about ten nanoseconds (Peterman, et al 1995), while the sub-nanosecond triplet Car generation was recently reported (Gall, et al 2011;Simova, et al 2022). It has been suggested that the two Cars bound to the D2 protein in PSII act as quenchers of singlet oxygen, generated via the triplet state of the primary electron donor (Telfer 2005).…”

“…Gradinaru, et al 2001;Papagiannakis, et al 2002;Simova, et al 2022), while the recent investigations have suggested the singlet ssion of Car S 2 or Bchl Q y to Car T 1(Niedzwiedzki, et al 2017;Uragami, et al 2020). Moreover, Jailaubekov et al, has reported the ultrafast triplet state generation directly from S 2 of β-Car in solution(Jailaubekov, et al 2011), while the observation cannot be explained by a singlet ssion due to a low molecular density.…”