Electronic Structure Effects Related to the Origin of the Remarkable Near-Infrared Absorption of Blastochloris viridis' Light Harvesting 1-Reaction Center Complex. 2022

Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
Centro Conjunto de Investigación en Química Sustentable UAEM-UNAM. Carretera Toluca-Atlacomulco Km. 14.5, Unidad San Cayetano. Toluca de Lerdo 50200, México.

Various photosynthetic organisms have evolved to absorb light in different regions of the visible light spectrum, thus adapting to the various lighting conditions available on Earth. While most of these autotrophic organisms absorb wavelengths around the 700-800 nm region, some are capable of red-shifted absorptions above this range, but none as remarkably as Blastochloris viridis whose main absorption is observed at 1015 nm, approximately 220 nm (0.34 eV) lower in energy than their main constituent pigments, BChl-b, whose main absorption is observed at 795 nm. The structure of its light harvesting 1-reaction center was recently elucidated by cryo-EM; however, the electronic structure details behind this red-shifted absorption remain unattended. We used hybrid quantum mechanics/molecular mechanics (QM/MM) calculations to optimize one of the active centers and performed classical molecular dynamics (MD) simulations to sample conformations beyond the optimized structure. We did excited state calculations with the time-dependent density functional theory method at the CAM-B3LYP/cc-pVDZ level of theory. We reproduced the near IR absorption by sequentially modifying the number of components involved in our systems using representative structures from the calculated MD ensemble. Natural transition orbital analysis reveals the participation of the BChl-b fragments to the main transition in the native structure and the structures obtained from the QM/MM and MD simulations. H-bonding pigment-protein interactions play a role on the conformation stabilization and orientation; however, the bacteriochlorin ring conformations and the exciton delocalization are the most relevant factors to explain the red-shifting phenomenon.

UI MeSH Term Description Entries
D010788 Photosynthesis The synthesis by organisms of organic chemical compounds, especially carbohydrates, from carbon dioxide using energy obtained from light rather than from the oxidation of chemical compounds. Photosynthesis comprises two separate processes: the light reactions and the dark reactions. In higher plants; GREEN ALGAE; and CYANOBACTERIA; NADPH and ATP formed by the light reactions drive the dark reactions which result in the fixation of carbon dioxide. (from Oxford Dictionary of Biochemistry and Molecular Biology, 2001) Calvin Cycle,Calvin-Benson Cycle,Calvin-Benson-Bassham Cycle,Carbon Fixation, Photosynthetic,Reductive Pentose Phosphate Cycle,Dark Reactions of Photosynthesis,Calvin Benson Bassham Cycle,Calvin Benson Cycle,Cycle, Calvin,Cycle, Calvin-Benson,Cycle, Calvin-Benson-Bassham,Photosynthesis Dark Reaction,Photosynthesis Dark Reactions,Photosynthetic Carbon Fixation
D004581 Electronics The study, control, and application of the conduction of ELECTRICITY through gases or vacuum, or through semiconducting or conducting materials. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed) Electronic
D045342 Light-Harvesting Protein Complexes Complexes containing CHLOROPHYLL and other photosensitive molecules. They serve to capture energy in the form of PHOTONS and are generally found as components of the PHOTOSYSTEM I PROTEIN COMPLEX or the PHOTOSYSTEM II PROTEIN COMPLEX. Antenna Complexes, Light-Harvesting,Light-Harvesting Antenna Complexes,Light-Harvesting Chlorophyll Protein,Light-Harvesting Chlorophyll Protein Complexes,Antenna Complexes, Light Harvesting,Chlorophyll Protein, Light-Harvesting,Complexes, Light-Harvesting Antenna,Complexes, Light-Harvesting Protein,Light Harvesting Antenna Complexes,Light Harvesting Chlorophyll Protein,Light Harvesting Chlorophyll Protein Complexes,Light Harvesting Protein Complexes,Protein Complexes, Light-Harvesting
D041921 Hyphomicrobiaceae A family in the order Rhizobiales, class ALPHAPROTEOBACTERIA comprised of many genera of budding or appendaged bacteria.

Related Publications

Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
January 2003, Photosynthesis research,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
May 2005, Acta crystallographica. Section D, Biological crystallography,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
January 2008, FEBS letters,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
April 1998, FEBS letters,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
January 2010, Journal of computational chemistry,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
March 2023, The Biochemical journal,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
January 2005, Acta crystallographica. Section F, Structural biology and crystallization communications,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
September 2009, Biochimica et biophysica acta,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
January 2006, The journal of physical chemistry. B,
Gustavo Mondragón-Solórzano, and Jacinto Sandoval-Lira, and Jorge Nochebuena, and G Andrés Cisneros, and Joaquín Barroso-Flores
April 2018, Nature,
Copied contents to your clipboard!