title: Crystallization of Photosystem II for Time-Resolved Structural Studies Using an X-ray Free Electron Laser.
abstract: Photosystem II (PSII) is a membrane protein supercomplex that executes the initial reaction of photosynthesis in higher plants, algae, and cyanobacteria. It captures the light from the sun to catalyze a transmembrane charge separation. In a series of four charge separation events, utilizing the energy from four photons, PSII oxidizes two water molecules to obtain dioxygen, four protons, and four electrons. The light reactions of photosystems I and II (PSI and PSII) result in the formation of an electrochemical transmembrane proton gradient that is used for the production of ATP. Electrons that are subsequently transferred from PSI via the soluble protein ferredoxin to ferredoxin-NADP(+) reductase that reduces NADP(+) to NADPH. The products of photosynthesis and the elemental oxygen evolved sustain all higher life on Earth. All oxygen in the atmosphere is produced by the oxygen-evolving complex in PSII, a process that changed our planet from an anoxygenic to an oxygenic atmosphere 2.5 billion years ago. In this chapter, we provide recent insight into the mechanisms of this process and methods used in probing this question.
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA.
authors.forename: Jesse
authors.initials: J
authors.lastname: Coe
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Kupitz
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA.
authors.forename: Shibom
authors.initials: S
authors.lastname: Basu
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA.
authors.forename: Chelsie E
authors.initials: CE
authors.lastname: Conrad
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA.
authors.forename: Shatabdi
authors.initials: S
authors.lastname: Roy-Chowdhury
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA.
authors.forename: Raimund
authors.initials: R
authors.lastname: Fromme
authors.affiliation: Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona, USA. Electronic address: petra.fromme@asu.edu.
authors.forename: Petra
authors.initials: P
authors.lastname: Fromme
mesh_terms: D003460:Crystallization / Q000295:instrumentation / Q000379:methods; D018360:Crystallography, X-Ray / Q000295:instrumentation / Q000379:methods*; D004583:Electrons; D004867:Equipment Design; D007834:Lasers; D008958:Models, Molecular; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000302:isolation & purification; D011487:Protein Conformation; D046940:Synechococcus / Q000737:chemistry*
chemical_list: D045332:Photosystem II Protein Complex
keywords: Femtosecond; Free electron laser; Free interface diffusion; Nanocrystallography; OEC; Photosynthesis; Photosystem II; Serial crystallography