Figure 2.

Crystal structure of GlnK1. (a) Cartoon diagram of the A. fulgidus GlnK1 monomer coloured from blue (N-terminus) to red (C-terminus). The inner core of the protein is composed of four antiparallel β-strands surrounded by two α-helices. The protruding T-loop located between strands 2 and 3 is partially disordered and residues 44–53 were therefore not modelled. (b) View along the threefold axis of the physiological trimer of the protein. (c) Sequence alignment of the three GlnK proteins from A. fulgidus with that from E. coli; residues that share 100–80% and 79–50% identity are shown in red and grey, respectively.