9N9A
Crystal structure of Class-3 OPX WzaB from Myxococcus xanthus
Summary for 9N9A
| Entry DOI | 10.2210/pdb9n9a/pdb |
| Descriptor | Polysaccharide export protein, GLYCEROL (3 entities in total) |
| Functional Keywords | polysaccharide secretion, lipoprotein, opx protein, transport, translocase |
| Biological source | Myxococcus xanthus DZ2 |
| Total number of polymer chains | 1 |
| Total formula weight | 20228.86 |
| Authors | Mellouk, A.,Calmettes, C. (deposition date: 2025-02-10, release date: 2026-01-28, Last modification date: 2026-02-04) |
| Primary citation | Mellouk, A.,Ngo, K.,Kezzo, A.A.,Martini, C.,Franca, T.C.C.,Laplante, S.R.,Islam, S.T.,Calmettes, C. Mechanism of trans-envelope bacterial polysaccharide secretion in Class-3 outer-membrane polysaccharide export (OPX) protein systems. Nat Commun, 17:732-732, 2026 Cited by PubMed Abstract: Bacterial secretion of extracellular polysaccharides is essential for surface colonization, biofilm formation, and pathogenesis. In diderm bacteria, such polymers traverse the periplasm and outer membrane (OM) through outer-membrane polysaccharide export (OPX) proteins that form secretion pores. Among them, Class-3 OPX proteins are the most widespread but lack an OM-spanning pore domain, leaving their mechanisms poorly understood. Here, we characterize WzaB from Myxococcus xanthus as a model for Class-3 OPX-mediated secretion. Structural and molecular dynamics analyses reveal that WzaB exists as a rigid monomer in solution, in contrast to the constitutive octamerization observed in Class-1 OPX proteins. Biochemical, biophysical, and in vivo analyses show that WzaB oligomerizes in a lipidation-dependent manner and directly interacts with the OM porin WzpB and the inner-membrane co-polymerase WzcB, with binding determinants mapped for both partners. Together, these proteins assemble into a trans-envelope polysaccharide secretion complex, redefining OPX function and revealing a distinct translocon architecture for Class-3 OPX systems. PubMed: 41545361DOI: 10.1038/s41467-025-67321-3 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.9 Å) |
Structure validation
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