nl6b04846_si_001.pdf (1.2 MB)
Orange Carotenoid Protein as a Control Element in an Antenna System Based on a DNA Nanostructure
journal contribution
posted on 2017-01-13, 00:00 authored by Alessio Andreoni, Su Lin, Haijun Liu, Robert E. Blankenship, Hao Yan, Neal W. WoodburyTaking
inspiration from photosynthetic mechanisms in natural systems, we
introduced a light-sensitive photo protective quenching element to
an artificial light-harvesting antenna model to control the flow of
energy as a function of light intensity excitation. The orange carotenoid
protein (OCP) is a nonphotochemical quencher in cyanobacteria: under
high-light conditions, the protein undergoes a spectral shift, and
by binding to the phycobilisome, it absorbs excess light and dissipates
it as heat. By the use of DNA as a scaffold, an antenna system made
of organic dyes (Cy3 and Cy5) was constructed, and OCP was assembled
on it as a modulated quenching element. By controlling the illumination
intensity, it is possible to switch the direction of excitation energy
transfer from the donor Cy3 to either of two acceptors. Under low-light
conditions, energy is transferred from Cy3 to Cy5, and under intense
illumination, energy is partially transferred to OCP as well. These
results demonstrate the feasibility of controlling the pathway of
energy transfer using light intensity in an engineered light-harvesting
system.