Neutron and X‐ray analysis of the Fenna–Matthews–Olson photosynthetic antenna complex from Prosthecochloris aestuarii

• Published in: Acta crystallographica. Section F, Structural biology communications Structural biology communications, 2019-03, Vol.75 (3), p.171-175
• Main Authors: Lu, Xun, Selvaraj, Brinda, Ghimire-Rijal, Sudipa, Orf, Gregory S., Meilleur, Flora, Blankenship, Robert E., Cuneo, Matthew J., Myles, Dean A. A.
• Format: Article
• Language: English
• Subjects: Antennas; Atomic structure; Chlorobi - chemistry; Chlorobi - physiology; Crystal growth; Crystallization; Crystals; Fenna–Matthews–Olson protein; hydrogen; Light-Harvesting Protein Complexes - chemistry; Lymphocytes B; neutron crystallography; Neutron diffraction; Neutron Diffraction - methods; Neutrons; Photosynthesis; Prosthecochloris aestuarii; Protein Conformation; Proteins; Research Communications; site energy; solar (fuels), photosynthesis (natural and artificial), biofuels (including algae and biomass), bio-inspired, charge transport, membrane, synthesis (novel materials), synthesis (self-assembly); Spallation; X-Ray Diffraction - methods
• ISSN: 2053-230X; 2053-230X
• DOI: 10.1107/S2053230X19000724

The Fenna–Matthews–Olson protein from Prosthecochloris aestuarii (PaFMO) has been crystallized in a new form that is amenable to high‐resolution X‐ray and neutron analysis. The crystals belonged to space group H3, with unit‐cell parameters a = b = 83.64, c = 294.78 Å, and diffracted X‐rays to ∼1.7 Å resolution at room temperature. Large PaFMO crystals grown to volumes of 0.3–0.5 mm3 diffracted neutrons to 2.2 Å resolution on the MaNDi neutron diffractometer at the Spallation Neutron Source. The resolution of the neutron data will allow direct determination of the positions of H atoms in the structure, which are believed to be fundamentally important in tuning the individual excitation energies of bacteriochlorophylls in this archetypal photosynthetic antenna complex. This is one of the largest unit‐cell systems yet studied using neutron diffraction, and will allow the first high‐resolution neutron analysis of a photosynthetic antenna complex. Large crystals of the Fenna–Matthews–Olson protein from Prosthecochloris aestuarii were grown in a new H3 space group that permitted room‐temperature neutron diffraction data collection to 2.2 Å resolution.