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-Structure paper
Title | Alternating L4 loop architecture of the bacterial polysaccharide co-polymerase WzzE. |
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Journal, issue, pages | Commun Biol, Vol. 6, Issue 1, Page 802, Year 2023 |
Publish date | Aug 2, 2023 |
Authors | Benjamin Wiseman / Göran Widmalm / Martin Högbom / |
PubMed Abstract | Lipopolysaccharides such as the enterobacterial common antigen are important components of the enterobacterial cell envelope that act as a protective barrier against the environment and are often ...Lipopolysaccharides such as the enterobacterial common antigen are important components of the enterobacterial cell envelope that act as a protective barrier against the environment and are often polymerized by the inner membrane bound Wzy-dependent pathway. By employing cryo-electron microscopy we show that WzzE, the co-polymerase component of this pathway that is responsible for the length modulation of the enterobacterial common antigen, is octameric with alternating up-down conformations of its L4 loops. The alternating up-down nature of these essential loops, located at the top of the periplasmic bell, are modulated by clashing helical faces between adjacent protomers that flank the L4 loops around the octameric periplasmic bell. This alternating arrangement and a highly negatively charged binding face create a dynamic environment in which the polysaccharide chain is extended, and suggest a ratchet-type mechanism for polysaccharide elongation. |
External links | Commun Biol / PubMed:37532793 / PubMed Central |
Methods | EM (single particle) |
Resolution | 2.5 - 3.5 Å |
Structure data | EMDB-16071, PDB-8bhw: EMDB-16072: Full-length bacterial polysaccharide co-polymerase WzzE from E. coli. C1 symmetry EMDB-16073: Full-length bacterial polysaccharide co-polymerase WzzE from E. coli. C8 symmetry EMDB-17387, PDB-8p3o: EMDB-17388: Full-length bacterial polysaccharide co-polymerase WzzE mutant R267A from E. coli. C1 symmetry EMDB-17389, PDB-8p3p: EMDB-17390: Full-length bacterial polysaccharide co-polymerase WzzE mutant R267E from E. coli. C1 symmetry |
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Keywords | MEMBRANE PROTEIN / Complex / Lipopolysaccharide / bacterial polysaccharide co-polymerase |