Abstract
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 Å, b = 86.3 Å, c = 81.5 Å, a =β = γ = 90° and diffract to about 2.3 resolution. An Analysis of the intensity data using an R(equiv) 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 Å. 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 Å = 65.7 Å and c = 121.8 Å and diffract to about 2.3 Å. Crystals of a selenomethionyl GlnBP (form B') are isomorphous to form B Crystals and diffract to about 2.1 Å resolution.