Crystallization and preliminary X-ray analysis of recombinant bovine cellular retinoic acid-binding protein

Crystals of bovine cellular retinoic acid-binding protein (CRABPI) have been grown from protein expressed in E. coli. Two different crystal forms were obtained. Crystals containing protein with the ligand all-trans retinoic acid belong to space group P4(1) or P4(3), a = b = 41.36, c = 202.71 A and diffract to 2.5 A. Crystals of CRABP with the synthetic retinoid analogue Am80 diffract to 1.9 A with space group P2(1) and cell dimensions a = 37.03, b = 105.93, c = 40.31 A, beta = 110.28 degrees. Considerations in the crystallization of proteins with light-sensitive ligands are discussed.