• N-acetyl-γ-glutamyl-phosphate reductase.

N-Acetyl-γ-glutamyl-phosphate reductase (AGPR) catalyses the NADPH-dependent reduction of N-acetyl-γ-glutamyl phosphate to give the N-acetylglutamic semialdehyde. A recombinant form of AGPR from Thermus thermophilus HB8 has been crystallized by the hanging-drop vapour-diffusion technique using PEG 4000 as a precipitating agent. The crystals grew as colourless prisms, with unit-cell parameters a = b = 90.9, c = 139.5 Å, α = β = 90, γ = 120°. The crystals belong to the hexagonal space group P6222 or P6422 and are most likely to contain a monomer in the asymmetric unit, with a VM value of 2.19 Å3 Da−1. The crystals diffract to a resolution of 2.2 Å at beamline BL44B2 of SPring-8.