Protein-Based Model for Energy Transfer between Photosynthetic Light-Harvesting Complexes Is Constructed Using a Direct Protein–Protein Conjugation Strategy

Abstract

Photosynthetic organisms utilize dynamic and complex networks of pigments bound within light-harvesting complexes to transfer solar energy from antenna complexes to reaction centers. Understanding the principles underlying the efficiency of these energy transfer processes, and how they may be incorporated into artificial light-harvesting systems, is facilitated by the construction of easily tunable model systems. We describe a protein-based model to mimic directional energy transfer between light-harvesting complexes using a circular permutant of the tobacco mosaic virus coat protein (cpTMV), which self-assembles into a 34-monomer hollow disk. Two populations of cpTMV assemblies, one labeled with donor chromophores and another labeled with acceptor chromophores, were coupled using a direct protein−protein bioconjugation method. Using potassium ferricyanide as an oxidant, assemblies containing o-aminotyrosine were activated toward the addition of assemblies containing p-aminophenylalanine. Both of these noncanonical amino acids were introduced into the cpTMV monomers through amber codon suppression. This coupling strategy has the advantages of directly, irreversibly, and site-selectively coupling donor with acceptor protein assemblies and avoids cross-reactivity with native amino acids and undesired donor−donor or acceptor−acceptor combinations. The coupled donor−acceptor model was shown to transfer energy from an antenna disk containing donor chromophores to a downstream disk containing acceptor chromophores. This model ultimately provides a controllable and modifiable platform for understanding photosynthetic interassembly energy transfer and may lead to the design of more efficient functional light-harvesting materials.

Impact of Ring-Closing on the Photophysical Properties of One-Dimensional π-Conjugated Molecular Aggregate

“…Currently, no general molecular design that affords toroidal structures in nano- to mesoscale has been established, but the formation of toroidal structures has been observed for several molecules in recent years. − Although no difference in properties between toroidal assemblies and linear counterparts is expected when the diameters of the formers approach microscale, the impact of ring-closing appears in a smaller scale (nano- to mesoscale) and we can see some differences in their properties, e.g., kinetic stabilities, ,,, secondary nucleation behaviors, ,,,, and photophysical properties as demonstrated in this study. Our study thus suggests that morphological control of materials in mesoscale could be a new guideline for the design of functional materials.…”

Heteromeric guanosine (G)-quadruplex derived antenna modules with directional energy transfer

“…1–11 These systems generally involve the use of synthetic templates (polymers, dendrimers, metal–organic frameworks) or biological scaffolds (such as protein-based viral capsids) to position dyes in a well-defined, nanometer regime, for light absorption and funneling. 12–24 Among the various scaffolding technologies, DNA is arguably unrivaled due to the diversity and programmability of 3D structures that can be assembled using DNA, with precision placement of dyes. 25–31 Further advantages of DNA include its compatibility with biological systems and facile post-synthesis modification.…”