Title: Excitonic Energy Landscape of the Y16F Mutant of the Chlorobium tepidum Fenna–Matthews–Olson (FMO) Complex: High Resolution Spectroscopic and Modeling Studies

Abstract

We report high-resolution (low-temperature) absorption, emission, and nonresonant/resonant hole-burned (HB) spectra and results of excitonic calculations using a non-Markovian reduced density matrix theory (with an improved algorithm for parameter optimization in heterogeneous samples) obtained for the Y16F mutant of the Fenna–Matthews–Olson (FMO) trimer from the green sulfur bacterium Chlorobium tepidum. We show that the Y16F mutant is a mixture of FMO complexes with three independent low-energy traps (located near 817, 821, and 826 nm), in agreement with measured composite emission and HB spectra. Two of these traps belong to mutated FMO subpopulations characterized by significantly modified low-energy excitonic states. Hamiltonians for the two major subpopulations (Sub₈₂₁ and Sub₈₁₇) provide new insight into extensive changes induced by the single-point mutation in the vicinity of BChl 3 (where tyrosine Y16 was replaced with phenylalanine F16). The average decay time(s) from the higher exciton state(s) in the Y16F mutant depends on frequency and occurs on a picosecond time scale.

Authors:

Khmelnitskiy, Anton ^[1]; Saer, Rafael G. ^[2]; Blankenship, Robert E. ^[2]; Jankowiak, Ryszard  ^[3]

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+ Show Author Affiliations

1. Kansas State Univ., Manhattan, KS (United States). Dept. of Chemistry
2. Washington Univ., St. Louis, MO (United States). Dept. of Biology and Chemistry
3. Kansas State Univ., Manhattan, KS (United States). Dept. of Chemistry, and Dept. of Physics

Publication Date:

Mon Mar 19 00:00:00 EDT 2018

Research Org.:

Energy Frontier Research Centers (EFRC) (United States). Photosynthetic Antenna Research Center (PARC)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1470597

Grant/Contract Number:  

SC0001035

Resource Type:

Journal Article: Accepted Manuscript

Journal Name:

Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

Additional Journal Information:

Journal Volume: 122; Journal Issue: 14; Related Information: PARC partners with Washington University in St. Louis (lead); University of California, Riverside; University of Glasgow, UK; Los Alamos National Laboratory; University of New Mexico; New Mexico Corsortium; North Carolina State University; Northwestern University; Oak Ridge National Laboratory; University of Pennsylvania; Sandia National Laboratories; University of Sheffield, UK; Journal ID: ISSN 1520-6106

Publisher:

American Chemical Society

Country of Publication:

United States

Language:

English

Subject:

59 BASIC BIOLOGICAL SCIENCES; solar (fuels); photosynthesis (natural and artificial); biofuels (including algae and biomass); bio-inspired; charge transport; membrane; synthesis (novel materials); synthesis (self-assembly)