Green flavoprotein from P. leiognathi: purification, characterization and identification as the product of the lux G(N) gene.

A green flavoprotein (GFP) was isolated and purified to homogeneity from Photobacterium leiognathi, strain 208. GFP is a homodimer of molecular weight 54,000 and contains two molecules of an unusual flavin per molecule of protein. Various biochemical characteristics including isoelectric point, trypsin and chymotrypsin degradation, SDS and temperature influence on subunit dissociation and the dissociation of the flavin chromophore, were investigated. The sequence of 23 N-terminal amino acids was determined and found to be concurrent with the N-terminal amino acid sequence encoded by the lux G(N) gene of P. leiognathi. This fact suggests that GFP is a structural component of the Photobacterium luminescence system.