Molecule of the Week (04)
The molecule of the week comes from an article that focuses on alpha-Ketocarboxylates and structural models for certain types of halogenases (Friese, S. J.; Kucera, B. E.; Young, V. G., Jr.; Que, L., Jr.; Tolman, W. B. Inorg. Chem., 2008, 47, 1324-1331). Sterically hindered alpha-ketocarboxylates are often used for halogenase models. This molecule and article are interesting because they demonstrate the role of a metal in a biochemically significant system. X-Ray crystal structures show that these complexes are very similar to the active site of a nonheme iron halogenase enzyme, SyrB2. Threonine is chlorinated in the active site of SyrB2 during the synthesis of an anti-fungal agent. It is significant that the molecule is a dimer as a crystal but in solution the dimers seem to be broken. My interpretation is that the complex is too bulky to effectively mimic the halogenase active site. More work and a greater understanding of the alpha-ketocarboxylate structures is needed to access complexes that mimic nonheme alpha-ketoacid-dependent enzyme active sites, in their structure and function.