Oligolysine induced excitation deactivation of the light–harvesting complex II in lipid nanodisc

The functions of the light-harvesting complex II (LHCII) of plant rely on the destination of chlorophyll excitation. To examine the effect of electrical charge on the LHCII excitation dynamics, we incoporate spinach LHCII and polycationic lysine octamer (K8) into lipid nanodisc, and compare its fluorescene dynamics to that of LHCII alone in lipid nanodisc. K8 binding induces fluorescence quantum yield decline for 18 % and lifetime shortening from 3.47 ns to 2.93 ns. Molecular dynamics simulation shows that K8 binds the N-terminal of LHCII A-helix, which induces the observed fluorescence quenching via influencing the charge transfer state of the terminal emitting chlorophylls.