Biochemical characterization of recombinant chicken Riboflavin carrier protein.

Chicken Riboflavin Carrier Protein (cRCP) transports riboflavin from the maternal circulation to the egg yolk for fetal development. The cRCP is a globular protein and structurally very stable due to the presence of nine intra-molecular disulphide bonds. The cRCP comprises of two domains; the larger riboflavin binding, and the smaller, oocyte receptor binding domain. With the objective to study domain folding in cRCP, these two domains of the corresponding gene were amplified, cloned, and expressed in a eukaryotic expression system to obtain soluble product. Our studies on the biochemical characterization of the recombinant proteins indicated that though the ligand binding domain assumed near-native conformation, as determined by immunological methods, it did not bind riboflavin, suggesting the interdependence of the two domains for proper organization of the riboflavin binding pocket.