Molecular origins of absorption wavelength variation among phycocyanobilin-binding proteins.

ABSTRACT: Phycocyanobilin (PCB)-binding proteins, including cyanobacteriochromes and phytochromes, function as photoreceptors and exhibit a wide range of absorption maximum wavelengths. To elucidate the color-tuning mechanisms among these proteins, we investigated seven crystal structures of six PCB-binding proteins: Anacy_2551g3, AnPixJg2, phosphorylation-responsive photosensitive histidine kinase, RcaE, Sb.phyB(PG)-PCB, and Slr1393g3. Employing a quantum chemical/molecular mechanical approach combined with a polarizable continuum model, our analysis revealed that differences in absorption wavelengths among PCB-binding proteins primarily arise from variations in the shape of the PCB molecule itself, accounting for a ∼150 nm difference. Remarkably, calculated excitation energies sufficiently reprodu

SUBMITTER: Noji T 

PROVIDER: S-EPMC11480761 | biostudies-literature | 2024 Oct

REPOSITORIES: biostudies-literature