5WP5

Arabidopsis thaliana phosphoethanolamine N-methyltransferase 2 (AtPMT2) in complex with SAH

Summary for 5WP5

• Entry DOI: 10.2210/pdb5wp5/pdb
• Descriptor: Phosphomethylethanolamine N-methyltransferase 2, S-ADENOSYL-L-HOMOCYSTEINE (3 entities in total)
• Functional Keywords: phosphoethanolamine n-methyltransferase, atpmt2, transferase
• Biological source: Arabidopsis thaliana (Mouse-ear cress)
• Total number of polymer chains: 2
• Total formula weight: 113768.21

Authors

Lee, S.G.,Jez, J.M. (deposition date: 2017-08-03, release date: 2017-11-15, Last modification date: 2023-10-04)

Primary citation

Lee, S.G.,Jez, J.M.
Conformational changes in the di-domain structure of Arabidopsis phosphoethanolamine methyltransferase leads to active-site formation.
J. Biol. Chem., 292:21690-21702, 2017

PubMed Abstract: Phosphocholine (pCho) is a precursor for phosphatidylcholine and osmoprotectants in plants. In plants, synthesis of pCho relies on the phosphobase methylation pathway. Phosphoethanolamine methyltransferase (PMT) catalyzes the triple methylation of phosphoethanolamine (pEA) to pCho. The plant PMTs are di-domain methyltransferases that divide the methylation of pEA in one domain from subsequent methylations in the second domain. To understand the molecular basis of this architecture, we examined the biochemical properties of three PMTs (AtPMT1-3) and determined the X-ray crystal structures of AtPMT1 and AtPMT2. Although each isoform synthesizes pCho from pEA, their physiological roles differ with AtPMT1 essential for normal growth and salt tolerance, whereas AtPMT2 and AtPMT3 overlap functionally. The structures of AtPMT1 and AtPMT2 reveal unique features in each methyltransferase domain, including active sites that use different chemical mechanisms for phosphobase methylation. These structures also show how rearrangements in both the active sites and the di-domain linker form catalytically competent active sites and provide insight on the evolution of the PMTs in plants, nematodes, and apicomplexans. Connecting conformational changes with catalysis in modular enzymes, like the PMT, provides new insights on interdomain communication in biosynthetic systems.

PubMed: 29084845
DOI: 10.1074/jbc.RA117.000106

Experimental method

X-RAY DIFFRACTION (1.5 Å)