Spectral signatures of canthaxanthin translocation in the orange carotenoid protein

• Autores: Pigni, Natalia Belen; Clark, Kevin L.; Beck, Warren F.; Gascón, José A.
• Año de publicación: 2020
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: OCP; CANTHAXANTHIN; QM/MM; METADYNAMICS
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

The orange carotenoid protein (OCP) is involved in the photoprotective processes in cyanobacteria via nonphotochemical quenching. Triggered by blue-green light absorption, the carotenoid chromophore undergoes translocation, displacing around 12 Å from the C-terminal domain (CTD) to the N-terminal domain (NTD). The detailed molecular rearrangements that occur within the carotenoid and the protein during this process remain largely elusive. By using a combination of molecular dynamics, well-tempered metadynamics, and hybrid quantum mechanical/molecular mechanical (QM/MM) calculations, we were able to mimic the translocation of the carotenoid from the inactive OCPO and obtain metastable red-shifted states in the photoactivation mechanism, replicating the λmax values of reference experimental spectra. In addition, our simulations give insight into the structure of the red-shifted form of the inactive state of OCP.
Fil: Pigni, Natalia Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina. University of Connecticut; Estados Unidos
Fil: Clark, Kevin L.. University of Connecticut; Estados Unidos
Fil: Beck, Warren F.. Michigan State University; Estados Unidos
Fil: Gascón, José A.. University of Connecticut; Estados Unidos