The purification, crystallization and preliminary structural characterization of PhzM, a phenazine-modifying methyltransferase from Pseudomonas aeruginosa.

Pyocyanin, phenazine-1-carboxylic acid and more than 70 related compounds collectively known as phenazines are produced by various species of Pseudomonas, including the fluorescent pseudomonad P. aeruginosa, a Gram-negative opportunistic pathogen in humans and animals. P. aeruginosa synthesizes a characteristic blue water-soluble compound called pyocyanin (1-hydroxy-5-methyl-phenazine). Two enzymes designated PhzM and PhzS are involved in the terminal steps of its synthesis and very little is known about these enzymes. In this study, PhzM, a dimeric S-adenosylmethionine-dependent methyltransferase, was purified and crystallized from PEG 3350/sodium cacodylate/sodium citrate pH 6.5. The crystals belong to space group P1, with unit-cell parameters a = 46.1, b = 61.8, c = 69.6 A, alpha = 96.3, beta = 106.6, gamma = 106.9 degrees . They contain one dimer in the asymmetric unit and diffract to a resolution of 1.8 A. Anomalous data to 2.3 A resolution have been collected from seleno-L-methionine-labelled PhzM.