Functionally important domains of PqsD. A) 3D structure of the PqsD dimer with functionally significant domains and the central cavity. PqsD is rendered as cartoon with flexible regions coloured in green. Water molecules present in the central cavity are shown as red spheres. B) Multiple sequence alignment of PqsD and homologous KAS-III enzymes. Abbreviations: Paer – Pseudomonas aeruginosa, Bamb – Burkholderia ambifaria, Ecoli – Escherichia coli, Aael – Aquifex aeolicus, Tther – Thermus thermophilus, Saur – Staphylococcus aureus, Efaec – Enterococcus faecalis, Sliv – Streptomyces lividans, Mtub – Mycobacterium tuberculosis.