Metal ions play critical roles throughout biochemistry, often facilitating the cleavage of the bond between the two atoms in an oxygen molecule in metalloenzymes. They are the key to oxidizing organic molecules and, in the case of photosynthesis, water. An international team of scientists carrying out research at the U.S. Department of Energy Office of Science’s Advanced Photon Source (APS) has homed in on the role of metal ions in a wide range of biological processes, from metabolism to photosynthesis. Their published results were the cover article for the May 1, 2013, issue of the Journal of the American Chemical Society.
The metal ions in question are not themselves redox active, meaning they can grab a single oxygen atom without suffering interfering side reactions. Commonly, these species are hooked up to a heme-type porphyrin molecule, the central unit in the blood protein hemoglobin and the light-sensitive unit in chlorophyll at the heart of photosynthesis.
The researchers from Ewha Womans University (Korea), Purdue University, Osaka University (Japan), and the Japan Science and Technology Agency built a simplified model of the natural metal-oxo compound (an oxygen atom bound only to one or more metal centers) using manganese in the IV oxidation state to which is attached a chemical group, or ligand, containing five nitrogen atoms—N,N-bis(2-pyridylmethyl)-N-bis(2-pyridyl) methylamine—which allow it to bond to the manganese(IV) through five points, with the final bonding point available for the oxo, or oxygen atom. Linking scandium ions to this unit completes the structure.
Read more at: Phys.org