Light Structures

摘要

Absorption of light by photosynthetic reaction centers causes structural changes and triggers a series of electron transfer reactions, resulting in a transmembrane potential difference that can be used to drive the subsequent chemistry. The initial electron transfer generates a charge-separated state that must be stabilized to prevent dissipation of energy through recombination. Woehri et al. (p. 630) have used time-resolved Laue diffraction crystallography to observe light-induced confor-mational changes that occur within milliseconds of photooxidation of the dimer of bacteriochloro-phyll molecules, known as the "special pair," in the photosynthetic reaction center of Blastochloris viridis. Stabilization appears to occur because of the deprotonation of a conserved tyrosine residue that moves closer to the special pair.