Figure 1.

Crystal structure of L. pneumophila PPase (LpPPase). (a) The homohexameric structure of LpPPase, which is a dimer of trimers, is shown. Individual monomers of the upper and lower trimer are colored in three different shades of green. All subunits are shown as ribbons. (b) One trimer is shown in surface representation, while the other is shown as ribbons. Individual subunits colored as in (a) demonstrating symmetry. (c) Representative monomer of LpPPase annotated with secondary-structure elements including β-sheets (β), α-helices (α) and 3₁₀-helices (η). (d) Secondary-structure elements involved in the quaternary-structure interfaces for each monomer are colored red and labeled, with the trimer–trimer interface boxed.