Molecular organization of the E. coli cellulose synthase macrocomplex

Nat Struct Mol Biol. 2021 Mar;28(3):310-318. doi: 10.1038/s41594-021-00569-7. Epub 2021 Mar 11.


Cellulose is frequently found in communities of sessile bacteria called biofilms. Escherichia coli and other enterobacteriaceae modify cellulose with phosphoethanolamine (pEtN) to promote host tissue adhesion. The E. coli pEtN cellulose biosynthesis machinery contains the catalytic BcsA-B complex that synthesizes and secretes cellulose, in addition to five other subunits. The membrane-anchored periplasmic BcsG subunit catalyzes pEtN modification. Here we present the structure of the roughly 1 MDa E. coli Bcs complex, consisting of one BcsA enzyme associated with six copies of BcsB, determined by single-particle cryo-electron microscopy. BcsB homo-oligomerizes primarily through interactions between its carbohydrate-binding domains as well as intermolecular beta-sheet formation. The BcsB hexamer creates a half spiral whose open side accommodates two BcsG subunits, directly adjacent to BcsA's periplasmic channel exit. The cytosolic BcsE and BcsQ subunits associate with BcsA's regulatory PilZ domain. The macrocomplex is a fascinating example of cellulose synthase specification.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Biocatalysis
  • Cellulose / metabolism*
  • Cryoelectron Microscopy
  • Escherichia coli / enzymology*
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / metabolism*
  • Escherichia coli Proteins / ultrastructure
  • Models, Molecular
  • Multienzyme Complexes / chemistry*
  • Multienzyme Complexes / metabolism*
  • Multienzyme Complexes / ultrastructure
  • Protein Subunits / chemistry
  • Protein Subunits / metabolism
  • Reproducibility of Results


  • Escherichia coli Proteins
  • Multienzyme Complexes
  • Protein Subunits
  • Cellulose