Advances in the Spectroscopic and Structural Characterization of Core Light-Harvesting Complexes from Purple Phototrophic Bacteria

J Phys Chem B. 2023 Jan 12;127(1):6-17. doi: 10.1021/acs.jpcb.2c06638. Epub 2023 Jan 3.

Abstract

Purple phototrophic bacteria are ancient anoxygenic phototrophs and attractive research tools because they capture light energy in the near-infrared (NIR) region of the spectrum and transform it into chemical energy by way of uphill energy transfers. The heart of this reaction occurs in light-harvesting 1-reaction center (LH1-RC) complexes, which are the simplest model systems for understanding basic photosynthetic reactions within type-II (quinone-utilizing) reaction centers. In this Perspective, we highlight structure-function relationships concerning unresolved fundamental processes in purple bacterial photosynthesis, including the diversified light-harvesting capacity of LH1-associated BChl molecules, energies necessary for photoelectric conversion in the RC special pairs, and quinone transport mechanisms. Based on recent progress in the spectroscopic and structural analysis of LH1-RC complexes from a variety of purple phototrophs, we discuss several key factors for understanding how purple bacteria resource light energy in the inherently energy-poor NIR region of the electromagnetic spectrum.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry
  • Cytoplasm / metabolism
  • Light-Harvesting Protein Complexes* / chemistry
  • Photosynthesis
  • Proteobacteria* / metabolism
  • Spectrum Analysis

Substances

  • Light-Harvesting Protein Complexes
  • Bacterial Proteins