Structural and Functional Characterization of Malate Synthase G from Opportunistic Pathogen Pseudomonas aeruginosa

Pseudomonas aeruginosa is an opportunistic human pathogen recognized as a critical threat by the World Health Organization because of the dwindling number of effective therapies available to treat infections. Over the past decade, it has become apparent that the glyoxylate shunt plays a vital role in sustaining P. aeruginosa during infection scenarios. The glyoxylate shunt comprises two enzymes: isocitrate lyase and malate synthase isoform G. Inactivation of these enzymes has been reported to abolish the ability of P. aeruginosa to establish infection in a mammalian model system, yet we still lack the structural information to support drug design efforts. In this work, we describe the first X-ray crystal structure of P. aeruginosa malate synthase G in the apo form at 1.62 A resolution. The enzyme is a monomer composed of four domains and is highly conserved with homologues found in other clinically relevant microorganisms. It is also dependent on Mg2+ for catalysis. Metal ion binding led to a change in th...