RLBP1 is a 36-kD water-soluble protein which carries 11-cis-retinaldehyde or 11-cis-retinal as physiologic ligands. It may be a functional component of the visual cycle. Mutations of this gene have been associated with severe rod-cone dystrophy, Bothnia dystrophy (nonsyndromic autosomal recessive retinitis pigmentosa) and retinitis punctata albescens. Recombinant human RLBP1 protein, fused to His-tag at N-terminus, was expressed in E.coli.