Single-Molecule Detection of the Encounter and Productive Electron Transfer Complexes of a Photosynthetic Reaction Center

• DOI: 10.1021/jacs.4c03913
• Publication Date: 2024-07-11T18:37:31Z
• Authors: Cvetelin Vasilev; Jon Nguyen; Adam G. M. Bowie; Guy E. Mayneord; Elizabeth C. Martin; Andrew Hitchcock; Taras V. Pogorelov; Abhishek Singharoy; C. Neil Hunter; Matthew P. Johnson
• Keywords: Rhodobacter sphaeroides

Small, diffusible redox proteins play an essential role in electron transfer (ET) respiration and photosynthesis, sustaining life on Earth by shuttling electrons between membrane-bound complexes via finely tuned reversible interactions. Ensemble kinetic studies show transient ET form two distinct stages: "encounter" complex largely mediated electrostatic interactions, which subsequently, through subtle reorganization of the binding interface, forms a "productive" stabilized additional hydrophobic interactions around redox-active cofactors. Here, using single-molecule force spectroscopy (SMFS) we dissected formed photosynthetic reaction center-light harvesting 1 (RC-LH1)