Crystals of glutamine-binding protein in various conformational states.

Crystals of glutamine-binding protein (GlnBP) in various conformational states have been obtained. Crystals of the ligand-free "open" state (denoted form B) have unit cell dimensions a = 86.3 A, b = 86.3 A, c = 81.5 A, alpha = beta = gamma = 90 degrees and diffract to about 2.3 A resolution. An analysis of the intensity data using an Requiv plot indicates that the crystal system is orthorhombic, space group P2(1)2(1)2(1). Crystals of the ligand-bound "open" state (form B*) are obtained by soaking form B crystals with glutamine (Gln) and diffract to about 1.9 A. Crystals of the GlnBP-Gln complex in a ligand-bound "closed" state (form C) belong to space group P2(1)2(1)2(1) with a = 62.0 A, b = 65.7 A and c = 121.8 A and diffract to about 2.3 A. Crystals of a selenomethionyl GlnBP (form B') are isomorphous to form B crystals and diffract to about 2.1 A resolution.