Application of cell-free translation systems to studies of cofactor binding proteins

To develop applications of in vitro cell-free translation systems for production and characterization of cofactor binding proteins, we investigate the production of apo- or holo-forms of Flavin Mono Nucleotide (FMN)-binding protein from Desulfovibrio vulgaris (Miyazaki F) and purified them. The redox potential analysis and measurements of UV-, visible, and fluorescent spectra of reconstructed holo-protein showed that the FMN correctly bound to the FMN binding site. On the other hand, contrary to our expectation, we found that the apo-protein formed a dimer structure and the incorporation of the FMN led the conformational alterations of the protein. These studies demonstrate the utility of cell-free translation systems to analyses of cofactor-binding proteins.