5OCE

THE MOLECULAR MECHANISM OF SUBSTRATE RECOGNITION AND CATALYSIS OF THE MEMBRANE ACYLTRANSFERASE PatA -- Complex of PatA with palmitate, mannose, and palmitoyl-6-mannose

Summary for 5OCE

• Entry DOI: 10.2210/pdb5oce/pdb
• Descriptor: Phosphatidylinositol mannoside acyltransferase, PALMITIC ACID, beta-D-mannopyranose, ... (5 entities in total)
• Functional Keywords: acyltransferase, glycolipid biosynthesis, transferase
• Biological source: Mycobacterium smegmatis (strain ATCC 700084 / mc(2)155)
• Cellular location: Cell membrane ; Single-pass membrane protein : A0QWG5
• Total number of polymer chains: 4
• Total formula weight: 136056.52

Authors

Albesa-Jove, D.,Tersa, M.,Guerin, M.E. (deposition date: 2017-06-30, release date: 2017-12-27, Last modification date: 2024-01-17)

Primary citation

Tersa, M.,Raich, L.,Albesa-Jove, D.,Trastoy, B.,Prandi, J.,Gilleron, M.,Rovira, C.,Guerin, M.E.
The Molecular Mechanism of Substrate Recognition and Catalysis of the Membrane Acyltransferase PatA from Mycobacteria.
ACS Chem. Biol., 13:131-140, 2018

PubMed Abstract: Glycolipids play a central role in a variety of important biological processes in all living organisms. PatA is a membrane acyltransferase involved in the biosynthesis of phosphatidyl-myo-inositol mannosides (PIMs), key structural elements, and virulence factors of Mycobacterium tuberculosis. PatA catalyzes the transfer of a palmitoyl moiety from palmitoyl-CoA to the 6-position of the mannose ring linked to the 2-position of inositol in PIM/PIM. We report here the crystal structure of PatA in the presence of 6-O-palmitoyl-α-d-mannopyranoside, unraveling the acceptor binding mechanism. The acceptor mannose ring localizes in a cavity at the end of a surface-exposed long groove where the active site is located, whereas the palmitate moiety accommodates into a hydrophobic pocket deeply buried in the α/β core of the protein. Both fatty acyl chains of the PIM acceptor are essential for the reaction to take place, highlighting their critical role in the generation of a competent active site. By the use of combined structural and quantum-mechanics/molecular-mechanics (QM/MM) metadynamics, we unravel the catalytic mechanism of PatA at the atomic-electronic level. Our study provides a detailed structural rationale for a stepwise reaction, with the generation of a tetrahedral transition state for the rate-determining step. Finally, the crystal structure of PatA in the presence of β-d-mannopyranose and palmitate suggests an inhibitory mechanism for the enzyme, providing exciting possibilities for inhibitor design and the discovery of chemotherapeutic agents against this major human pathogen.

PubMed: 29185694
DOI: 10.1021/acschembio.7b00578

Experimental method

X-RAY DIFFRACTION (2.41 Å)