Cellular retinol binding protein

Cowan, S. W., Newcomer, M. E., Jones, T. A.: Crystallographic studies on a family of cellular lipophilic transport proteins. Refinement of P2 myelin protein and the structure determination and refinement of cellular retinol-binding protein in complex with all-trans-retinol. J Mol Biol 230 pp. 1225 (1993) (PubMed)

1crb (PDB)

		Cartoons view of Cellular Retinol Binding Protein, an up-an-down 10-stranded beta barrel. There are 2 alpha-helices between strands 1 and 2.
		The retinol binds inside the barrel. The H-bonds are shown, indicating that one edge is not sealed (between 2 green strands).
		A spacefilling view shows that the retinol is almost buried. (Remember, it is a nonpolar molecule.) The helices are colored magenta. Now click button 1 to see how the helices close one end of the barrel.