Dynamics and mechanism of dimer dissociation of photoreceptor UVR8

• Published in: Nature communications Vol. 13; no. 1; p. 93
• Main Authors: Li, Xiankun, Liu, Zheyun, Ren, Haisheng, Kundu, Mainak, Zhong, Frank W., Wang, Lijuan, Gao, Jiali, Zhong, Dongping
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 10.01.2022; Nature Publishing Group; Nature Portfolio
• Subjects: 140/125; 631/449/2686; 631/57/2272/1590; 639/638/439/944; Anions; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Arginine - chemistry; Arginine - metabolism; Binding Sites; Chromosomal Proteins, Non-Histone - chemistry; Chromosomal Proteins, Non-Histone - genetics; Chromosomal Proteins, Non-Histone - metabolism; Cloning, Molecular; Computer applications; Dimers; Escherichia coli - genetics; Escherichia coli - metabolism; Flooding; Gene Expression; Genetic Vectors - chemistry; Genetic Vectors - metabolism; Humanities and Social Sciences; Kinetics; Mathematical analysis; Molecular Dynamics Simulation; Monomers; multidisciplinary; Mutation; Neutralization; Photoreceptors; Protein Binding; Protein Conformation, alpha-Helical; Protein Conformation, beta-Strand; Protein Interaction Domains and Motifs; Protein Multimerization; Quantum Theory; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Science; Science (multidisciplinary); Separation; Spectroscopy; Spectrum analysis; Static Electricity; Thermodynamics; Tryptophan; Tryptophan - chemistry; Tryptophan - metabolism; Ultraviolet Rays; Water - chemistry; Water - metabolism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-27756-w

Photoreceptors are a class of light-sensing proteins with critical biological functions. UVR8 is the only identified UV photoreceptor in plants and its dimer dissociation upon UV sensing activates UV-protective processes. However, the dissociation mechanism is still poorly understood. Here, by integrating extensive mutations, ultrafast spectroscopy, and computational calculations, we find that the funneled excitation energy in the interfacial tryptophan (Trp) pyramid center drives a directional Trp-Trp charge separation in 80 ps and produces a critical transient Trp anion, enabling its ultrafast charge neutralization with a nearby positive arginine residue in 17 ps to destroy a key salt bridge. A domino effect is then triggered to unzip the strong interfacial interactions, which is facilitated through flooding the interface by channel and interfacial water molecules. These detailed dynamics reveal a unique molecular mechanism of UV-induced dimer monomerization. UVR8 is a plant photoreceptor that dissociates into monomers after sensing UV. Here, via ultrafast spectroscopy and computational calculations, the authors describe the dynamics of charge separation and charge neutralization in UVR8 and describe how these unzip interactions at the dimer interface.