... In the center there is a schematicof the mutual relationship of the monomers,in selected members of the family, as indi-cated by the twist angle of the dimer.TM1415 constitutes one of the ... enclosed by the solidboxes. The contact on the left hand sidecomprises the active site loop (residues22–42), shown in detail in Figs 3 and 4. At the other side of the tetramer, the activesite ... architecture of the dimer is reminiscent of the human IMPase (Fig. 1,right panel). However, the dimer interface is quite dif-ferent from the human enzyme and other nonarchaealIMPases. The superposition...