Structure of TTHA1623, a novel metallo-beta-lactamase superfamily protein from Thermus thermophilus HB8.

TTHA1623 is a metallo-beta-lactamase superfamily protein from the extremely thermophilic bacterium Thermus thermophilus HB8. Homologues of TTHA1623 exist in a wide range of bacteria and archaea and one eukaryote, Giardia lamblia, but their function remains unknown. To analyze the structural properties of TTHA1623, the crystal structures of its iron-bound and zinc-bound forms have been determined to 2.8 and 2.2 A resolution, respectively. TTHA1623 possesses an alphabetabetaalpha-fold similar to that of other metallo-beta-lactamase superfamily proteins with glyoxalase II-type metal coordination. However, TTHA1623 exhibits a putative substrate-binding pocket with a unique shape.