A triclinic crystal form of the lectin concanavalin A

The molecular structure of a triclinic crystal form of concanavalin A has been refined at 2.4 Å resolution. The crystals have unit cell dimensions a = 78.8 Å, b = 79.3 Å, c = 133.3 Å, α = 97.1°, β = 90.2°, and γ = 97.5° and contain two tetramers per asymmetric unit each with approximate 222 symmetry. The final crystallographic R-factor is 0.205 and the free-R-factor is 0.265 in the resolution range 6.0 to 2.4 Å. The conformation of the tetramer is more similar to that found in concanavalin A saccharide complexes than in the previously reported I222 crystal form of uncomplexed concanavalin A. A comparison of the molecular packing between the two crystal forms shows a more open arrangement with large solvent channels through the crystal.