Crystallization of the virulent and benign subtilisin-like proteases from the ovine footrot pathogen Dichelobacter nodosus

Dichelobacter nodosus is the principal causative agent of ovine footrot, a disease of significant economic importance to the sheep industry. D. nodosus secretes a number of subtilisin-like serine proteases which mediate tissue damage and presumably contribute to the pathogenesis of footrot. Strains causing virulent footrot secrete the proteases AprV2, AprV5 and BprV and strains causing benign footrot secrete the closely related proteases AprB2, AprB5 and BprB. Here, the cloning, purification and crystallization of AprV2, AprB2, BprV and BprB are reported. Crystals of AprV2 and AprB2 diffracted to 2.0 and 1.7 Å resolution, respectively. The crystals of both proteases belonged to space group P1, with unit-cell parameters a = 43.1, b = 46.0, c = 47.2 Å, α = 97.8, β = 115.2, γ = 115.2° for AprV2 and a = 42.7, b = 45.8, c = 45.7 Å, α = 98.4, β = 114.0, γ = 114.6° for AprB2. Crystals of BprV and BprB diffracted to 2.0 and 1.8 Å resolution, respectively. The crystals of both proteases belonged to space group P2₁, with unit-cell parameters a = 38.5, b = 89.6, c = 47.7 Å, β = 113.6° for BprV and a = 38.5, b = 90.5, c = 44.1 Å, β = 109.9° for BprB. The crystals of all four proteases contained one molecule in the asymmetric unit, with a solvent content ranging from 36 to 40%.