Synthesis, characterization and X-ray crystal structure of an iron(III) complex of a tripodal pyridoxal Schiff base ligand: effects of positional disorder on its magnetic properties

Mechanistic Studies on the Single-Turnover Yeast Thiamin Pyrimidine Synthase: Characterization of the Inactive Enzyme

“…Inspection of the THI5p-PLP structure and analysis of all available THI5p sequences does not reveal a canonical protein iron binding site close to the active site. Therefore, based on the extensive literature on the Fe­(II) binding to salicylaldimine Schiff base ligands, − we propose that the PLP imine and hydroxyl groups constitute two of the Fe­(II)-binding ligands of THI5p, and the required 10/12-electron oxidation can be achieved using three cycles of closely related Fe­(III) superoxide oxidation chemistry. , Analogous Fe­(III) superoxide chemistry has been proposed for tryptophan dioxygenase, extradiol dioxygenases, − 2-oxoacid dioxygenases, and Rieske dioxygenases . A striking feature of the THI5p structure is the existence of a highly conserved set of four cysteine residues (Cys195, 196, 197, and 199) providing a path for electron transfer from the buffer to the active site by disulfide interchange reactions analogous to those found in the Class I ribonucleotide reductases .…”