Molecular ruler mechanism and interfacial catalysis of the integral membrane acyltransferase PatA.
Anso, I., Basso, L.G.M., Wang, L., Marina, A., Paez-Perez, E.D., Jager, C., Gavotto, F., Tersa, M., Perrone, S., Contreras, F.X., Prandi, J., Gilleron, M., Linster, C.L., Corzana, F., Lowary, T.L., Trastoy, B., Guerin, M.E.(2021) Sci Adv 7: eabj4565-eabj4565
- PubMed: 34652941 
- DOI: https://doi.org/10.1126/sciadv.abj4565
- Primary Citation of Related Structures:  
7OJT - PubMed Abstract: 
Glycolipids are prominent components of bacterial membranes that play critical roles not only in maintaining the structural integrity of the cell but also in modulating host-pathogen interactions. PatA is an essential acyltransferase involved in the biosynthesis of phosphatidyl- myo -inositol mannosides (PIMs), key structural elements and virulence factors of Mycobacterium tuberculosis . We demonstrate by electron spin resonance spectroscopy and surface plasmon resonance that PatA is an integral membrane acyltransferase tightly anchored to anionic lipid bilayers, using a two-helix structural motif and electrostatic interactions. PatA dictates the acyl chain composition of the glycolipid by using an acyl chain selectivity “ruler.” We established this by a combination of structural biology, enzymatic activity, and binding measurements on chemically synthesized nonhydrolyzable acyl–coenzyme A (CoA) derivatives. We propose an interfacial catalytic mechanism that allows PatA to acylate hydrophobic PIMs anchored in the inner membrane of mycobacteria, through the use of water-soluble acyl-CoA donors.
Organizational Affiliation: 
Structural Glycobiology Laboratory, Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 801A, 48160 Derio, Spain.