Igni18, a novel metallo‐hydrolase from the hyperthermophilic archaeon Ignicoccus hospitalis KIN4/I: cloning, expression, purification and X‐ray analysis

The hyperthermophilic crenarchaeon Ignicoccus hospitalis KIN4/I possesses at least 35 putative genes encoding enzymes that belong to the α/β‐hydrolase superfamily. One of those genes, the metallo‐hydrolase‐encoding igni18 , was cloned and heterologously expressed in Pichia pastoris . The enzyme produced was purified in its catalytically active form. The recombinant enzyme was successfully crystallized and the crystal diffracted to a resolution of 2.3 Å. The crystal belonged to space group R 32, with unit‐cell parameters a = b = 67.42, c  = 253.77 Å, α = β = 90.0, γ = 120.0°. It is suggested that it contains one monomer of Igni18 within the asymmetric unit.