Static Disorder has Dynamic Impact on Energy Transport in Biomimetic Light-Harvesting Complexes

J Phys Chem B. 2022 Oct 13;126(40):7981-7991. doi: 10.1021/acs.jpcb.2c06614. Epub 2022 Oct 3.

Abstract

Despite extensive studies, many questions remain about what structural and energetic factors give rise to the remarkable energy transport efficiency of photosynthetic light-harvesting protein complexes, owing largely to the inability to synthetically control such factors in these natural systems. Herein, we demonstrate energy transfer within a biomimetic light-harvesting complex consisting of identical chromophores attached in a circular array to a protein scaffold derived from the tobacco mosaic virus coat protein. We confirm the capability of energy transport by observing ultrafast depolarization in transient absorption anisotropy measurements and a redshift in time-resolved emission spectra in these complexes. Modeling the system with kinetic Monte Carlo simulations recapitulates the observed anisotropy decays, suggesting an inter-site hopping rate as high as 1.6 ps-1. With these simulations, we identify static disorder in orientation, site energy, and degree of coupling as key remaining factors to control to achieve long-range energy transfer in these systems. We thereby establish this system as a highly promising, bottom-up model for studying long-range energy transfer in light-harvesting protein complexes.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomimetics*
  • Energy Transfer
  • Light-Harvesting Protein Complexes / chemistry
  • Photosynthesis
  • Tobacco Mosaic Virus* / chemistry

Substances

  • Light-Harvesting Protein Complexes