Structure of L-arabinose-binding protein from Escherichia coli at 5 A resolution and preliminary results at 3.5 A.

Abstract
The 3-dimensional crystal structure of the L-arabinose-binding protein from E. coli, an essential component in the active transport of L-arabinose, was resolved at 5 .ANG. resolution using the method of multiple isomorphous replacement. Five heavy atom derivatives were used. A preliminary 3.5 .ANG. electron density map was also calculated. The molecule is ellipsoidal with approximate dimensions 68 .ANG. .times. 38 .ANG. .times. 30 .ANG.. Two similar domains within the molecule (which is a single polypeptide chain) are related by an approximate noncrystallographic rotation-translation axis. This relationship involves approximately 20% of the structure.