Structure elucidation and preliminary assessment of hydrolase activity of PqsE, the Pseudomonas quinolone signal (PQS) response protein

The crystal structure of recombinant PqsE, the Pseudomonas quinolone signal (PQS) response protein was characterized to show that it possesses a metallo-[beta]-lactamase fold with an Fe(II)Fe(III) center in the active site. Higher activity observed after incubation with [Co.sup.2+] and, to lesser extent, [Mn.sup.2+], suggested that the Fe(II)Fe(III) center of recombinant PqsE might be an artifact of heterologous expression.