3UJ6

SeMet Phosphoethanolamine methyltransferase from Plasmodium falciparum in complex with SAM and PO4

Summary for 3UJ6

• Entry DOI: 10.2210/pdb3uj6/pdb
• Related: 3UJ7 3UJ8 3UJ9 3UJA 3UJB 3UJC 3UJD
• Descriptor: Phosphoethanolamine N-methyltransferase, S-ADENOSYLMETHIONINE, PHOSPHATE ION, ... (4 entities in total)
• Functional Keywords: plasmodium, parasite, methyltransferase, transferase
• Biological source: Plasmodium falciparum
• Total number of polymer chains: 1
• Total formula weight: 31765.11

Authors

Lee, S.G.,Kim, Y.,Alpert, T.D.,Nagata, A.,Jez, J.M. (deposition date: 2011-11-07, release date: 2011-11-30, Last modification date: 2012-03-21)

Primary citation

Lee, S.G.,Kim, Y.,Alpert, T.D.,Nagata, A.,Jez, J.M.
Structure and reaction mechanism of phosphoethanolamine methyltransferase from the malaria parasite Plasmodium falciparum: an antiparasitic drug target.
J.Biol.Chem., 287:1426-1434, 2012

PubMed Abstract: In the malarial parasite Plasmodium falciparum, a multifunctional phosphoethanolamine methyltransferase (PfPMT) catalyzes the methylation of phosphoethanolamine (pEA) to phosphocholine for membrane biogenesis. This pathway is also found in plant and nematodes, but PMT from these organisms use multiple methyltransferase domains for the S-adenosylmethionine (AdoMet) reactions. Because PfPMT is essential for normal growth and survival of Plasmodium and is not found in humans, it is an antiparasitic target. Here we describe the 1.55 Å resolution crystal structure of PfPMT in complex with AdoMet by single-wavelength anomalous dispersion phasing. In addition, 1.19-1.52 Å resolution structures of PfPMT with pEA (substrate), phosphocholine (product), sinefungin (inhibitor), and both pEA and S-adenosylhomocysteine bound were determined. These structures suggest that domain rearrangements occur upon ligand binding and provide insight on active site architecture defining the AdoMet and phosphobase binding sites. Functional characterization of 27 site-directed mutants identifies critical active site residues and suggests that Tyr-19 and His-132 form a catalytic dyad. Kinetic analysis, isothermal titration calorimetry, and protein crystallography of the Y19F and H132A mutants suggest a reaction mechanism for the PMT. Not only are Tyr-19 and His-132 required for phosphobase methylation, but they also form a "catalytic" latch that locks ligands in the active site and orders the site for catalysis. This study provides the first insight on this antiparasitic target enzyme essential for survival of the malaria parasite; however, further studies of the multidomain PMT from plants and nematodes are needed to understand the evolutionary division of metabolic function in the phosphobase pathway of these organisms.

PubMed: 22117061
DOI: 10.1074/jbc.M111.315267

Experimental method

X-RAY DIFFRACTION (1.974 Å)