Mechanistic studies of mycobacterial glycolipid biosynthesis by the mannosyltransferase PimE
Tuberculosis (TB), a leading cause of death among infectious diseases globally, is caused by Mycobacterium tuberculosis (Mtb). The pathogenicity of Mtb is largely attributed to its complex cell envelope, which includes a class of glycolipids called phosphatidyl-myo-inositol mannosides (PIMs). These glycolipids maintain the integrity of the cell envelope, regulate permeability, and mediate host-pathogen interactions. PIMs comprise a phosphatidyl-myo-inositol core decorated with one to six mannose residues and up to four acyl chains. The mannosyltransferase PimE catalyzes the transfer of the fifth PIM mannose residue from a polyprenyl phosphate-mannose (PPM) donor. This step contributes to the proper assembly and function of the mycobacterial cell envelope; however, the structural basis for substrate recognition and the catalytic mechanism of PimE remain poorly understood. Here, we present the cryo-electron microscopy (cryo-EM) structures of PimE from Mycobacterium abscessus in its apo and product-bound form. The structures reveal a distinctive binding cavity that accommodates both donor and acceptor substrates/products. Key residues involved in substrate coordination and catalysis were identified and validated via in vitro assays and in vivo complementation, while molecular dynamics simulations delineated access pathways and binding dynamics. Our integrated approach provides comprehensive insights into PimE function and informs potential strategies for anti-TB therapeutics.
Authors
- Todd L. Lowary (ORCID: https://orcid.org/0000-0002-8331-8211)
- Sabrina I. Giacometti (ORCID: https://orcid.org/0000-0002-8291-7722)
- Meagan Belcher Dufrisne (ORCID: https://orcid.org/0000-0002-7961-4405)
- Rodrigo N. Nobre
- Rosemary J. Cater (ORCID: https://orcid.org/0000-0003-4503-002X)
- Filippo Mancia (ORCID: https://orcid.org/0000-0003-3293-2200)
- Yasu S. Morita (ORCID: https://orcid.org/0000-0002-4514-9242)
- Cristina G. Timóteo (ORCID: https://orcid.org/0000-0002-1612-6682)
- Rie Nygaard (ORCID: https://orcid.org/0000-0002-0425-234X)
- Satchal K. Erramilli (ORCID: https://orcid.org/0000-0001-8694-7681)
- Brian Kloss (ORCID: https://orcid.org/0000-0003-0130-8739)
- Phillip J. Stansfeld (ORCID: https://orcid.org/0000-0001-8800-7669)
- Yaqi Liu (ORCID: https://orcid.org/0009-0008-3066-797X)
- Chelsea M. Brown (ORCID: https://orcid.org/0000-0003-2006-5015)
- Anthony A. Kossiakoff (ORCID: https://orcid.org/0000-0003-3174-9359)
- Piotr Tokarz (ORCID: https://orcid.org/0000-0002-7618-7540)
- Helena Santos (ORCID: https://orcid.org/0000-0002-8050-9485)
- Nuno Borges (ORCID: https://orcid.org/0000-0002-3277-8517)
- Ana M. Esteves
Institutions
- University of Alberta (CA)
- The University of Queensland (AU)
- National Taiwan University (TW)
- University of Groningen (NL)
- Cornell University (US)
- University of Massachusetts Amherst (US)
- Columbia University Irving Medical Center (US)
- University of Warwick (GB)
- University of Chicago (US)
- Institute of Biological Chemistry, Academia Sinica (TW)
- Universidade Politécnica de Setúbal (PT)
- University of Virginia (US)
- New York University (US)
- Universidade Nova de Lisboa (PT)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-04-29
- DOI
- https://doi.org/10.1038/s41467-025-57843-1
- Citations
- 1
- Primary Topic
- Tuberculosis Research and Epidemiology
- Type
- article
- Field-Weighted Citation Impact
- 1.40
Funders
- University of Warwick
- National Institutes of Health
- Medical Research Council
- Engineering and Physical Sciences Research Council
- Biotechnology and Biological Sciences Research Council
- National Institute of General Medical Sciences