TRIGONAL CRYSTALS OF PORIN FROM ESCHERICHIA-COLI

Trigonal crystals of the integral membrane protein porin from Escherichia coli have been grown and characterized. They belong to space group P321 with unit cell constants a = b = 118.4, c = 52.7 A ̊, α = β = 90{ring operator}, γ = 120{ring operator}. The crystals grow as well-defined hexagonal prisms to a size of 0.25 mm in all dimensions, and diffract to 2.7 Å. The molecular symmetry coincides with 3-fold crystallographic symmetry, giving two trimers per unit cell (1 monomer/asymmetric unit). This corresponds to VM = 2.9A ̊3/Da. Native X-ray data to 3.0 Å resolution have been collected on a FAST area detector and a search for heavy atom derivatives is underway. © 1991.