Science 333: This electron transfer is aided by the presence of a nonheme iron located midway between them. Wendelstein 7-X produces first hydrogen plasma January 29, 2016.
The uncertainty of the cubane model was dismissed with the most recent 1. Insights gleaned from the recent structural determination of PSII have initiated considerable efforts to identify artificial catalytic systems for water oxidation and hydrogen production using solar energy Eisenberg and Gray 2008.
Science 277: C , Reprinted, with permission, from Ferreira et al. In the course of this process, plants, algae and cyanobacteria blue-green algae use sunlight to split water and produce energy-rich chemical compounds from carbon dioxide CO 2.
There are also a number of other low-molecular-mass transmembrane subunits that are rather featureless except for two that bind the high-potential heme of cytochrome b 559 Cyt b 559.
Cyanobacterial photosystem II at 2. Figure 3. The Ferreira et al. A structure-consistent mechanism for dioxygen formation in photosystem II. Finally, the PSIIRC core complex contains several extrinsic proteins attached to its lumenal surface that form a protein shield over the catalytic site of water splitting. Possible hydrogen bonds are also proposed and shown as light-blue dotted lines.
Furthermore, as postulated by Ferreira et al. Biochim Biophys Acta 1767: The scientists are investigating a particularly important cofactor involved in photosysthesis, a manganese-calcium complex, which uses solar energy to split water into molecular oxygen.
The only clear exceptions are that one of the ligands for the nonheme Fe of PSII is a bicarbonate ion and not a glutamate, as in bacteria, and the Q B site is a little larger and in closer contact with the stromal surface than in the bacterial RC.
This complex is composed of four manganese atoms Mn and one calcium atom Ca , which are held together through a network of oxygen bridges see image. X-ray crystallography identifies two chloride binding sites in the oxygen evolving centre of photosystem II.