Structure of recombinant prolidase from Thermococcus sibiricus in space group P2₁22₁

The crystal structure of recombinant prolidase from Thermococcus sibiricus was determined by X-ray diffraction at a resolution of 2.6 Å and was found to contain a tetramer in the asymmetric unit. A protein crystal grown in microgravity using the counter-diffusion method was used for X-ray studies. The crystal belonged to space group P2₁22₁, with unit-cell parameters a = 97.60, b = 123.72, c = 136.52 Å, α = β = γ = 90°. The structure was refined to an R_cryst of 22.1% and an R_free of 29.6%. The structure revealed flexible folding of the N-terminal domain of the protein as well as high variability in the positions of the bound metal ions. The coordinates of the resulting model were deposited in the Protein Data Bank as entry 4rgz.