Conformational dynamics and membrane insertion mechanism of B4GALNT1 in ganglioside synthesis
Year: 2025
Type: article
Abstract: Glycosphingolipids (GSLs) are crucial membrane components involved in essential cellular pathways. Complex GSLs, known as gangliosides, are synthesised by glycosyltransferase enzymes and imbalances in GSL metabolism cause severe neurological diseases. B4GALNT1 synthesises the precursors to the major brain gangliosides. Loss of B4GALNT1 function causes hereditary spastic paraplegia, while its overexpression is linked to cancers including childhood neuroblastoma. Here, we present crystal structures of the human homodimeric B4GALNT1 enzyme demonstrating dynamic remodelling of the substrate binding site during catalysis. We show that processing of lipid substrates by B4GALNT1 is severely compromised when surface loops flanking the active site are mutated from hydrophobic residues to polar. Molecular dynamics simulations support that these loops can insert into the lipid bilayer explaining how B4GALNT1 accesses and processes lipid substrates. By combining structure prediction and molecular simulations we propose that this mechanism of dynamic membrane insertion is exploited by other, structurally distinct GSL synthesising enzymes.
Source: Nature Communications
Institutions: University of Cambridge, University of Warwick
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $6,990
Funders: Wellcome Trust, Diamond Light Source, Joint Programming Initiative on Antimicrobial Resistance, University of Warwick, National Institutes of Health, Medical Research Council, Engineering and Physical Sciences Research Council, Biotechnology and Biological Sciences Research Council, Cambridge Institute for Medical Research, University of Cambridge, National Institute of Allergy and Infectious Diseases
Awards: G1702177393, Cell Wall Formation in Rod Shaped Bacteria, Optimal cell factories for membrane protein production, G339059223, The UK High-End Computing Consortium for Biomolecular Simulation, G3543272834, G3835265546, FtsEX-PcsB: A protein complex required for cell division in the bacterial pathogen S. pneumoniae, G4310967859, G4884426060, Antimicrobial Resistance: Breakthrough Compound Discovery through Mechanistic Studies combined with Bicycle Technology and Target Validation, Multidisciplinary toolbox for characterising lipid II binding antibiotics, G9000124366, G9000158989, The role of cardiolipin in the biogenesis of the Gram-negative bacterial cell envelope, The role of glycosphingolipids in modulating membrane protein trafficking
OpenAlex ID: W4411895408