The structure of a rhombohedral R6 insulin hexamer that binds phenol.
Different hexameric forms of insulin have been crystallized from a variety of conditions. In the presence of 1% phenol, 1.0 M sodium chloride, and at a pH of 8.5, a rhombohedral form is produced with two monomers in the asymmetric unit, space group R3, a = 79.92 A and c = 40.39 A. The structure has been solved and refined, using data between 8.0 and 2.5 A resolution, to a residual of 0.157. Each of the monomers adopts an R conformation, that is residues B1-B8 are alpha-helical. As a result of the T to R transition, an elliptical cavity is created between symmetry-related monomers and is occupied by a phenol molecule. A region of density within bonding distance to one of the zinc ions has been interpreted as an additional phenol molecule.
Smith
G D
GD
Medical Foundation of Buffalo, Inc., New York 14203.
Dodson
G G
GG
D003460:Crystallization; D007328:Insulin / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D010636:Phenols / Q000378:metabolism*; D011487:Protein Conformation
D007328:Insulin; D010636:Phenols