The molecular basis of regulation of bacterial capsule assembly by Wzc

ABSTRACT: Bacterial extracellular polysaccharides (EPSs) play critical roles in virulence as well as representing valuable bioproducts. Many bacteria use a “Wzx-Wzy-dependent” mechanism to assemble EPSs, in a tightly controlled multi-protein process that couples glycan polymerisation at the inner membrane to translocation across the periplasm and outer membrane (OM). The tyrosine autokinase, Wzc, is required for both polymerization and translocation. The cryo-EM structure of dephosphorylated Wzc from E. coli reveals an octameric structure, where transmembrane helices create a large central cavity and connect the cytoplasmic tyrosine kinase domain to a periplasmic region containing helical bundles. Progressive autophosphorylation of Wzc’s tyrosine-rich C-terminus disassembles the octamer into a monomer and the cycling between these states in the cell drives function. The helical bundles are essential for function and their conformation responds to phosphorylation; most likely gating the OM translocase. We propose a molecular model for the regulation of EPS synthesis and transport by Wzc.

INSTRUMENT(S): Orbitrap Eclipse

ORGANISM(S): Escherichia Coli

SUBMITTER: Jani Bolla  

LAB HEAD: Carol V Robinson

PROVIDER: PXD025820 | Pride | 2021-07-06

REPOSITORIES: Pride