Fig. 5: Cellulase activity is necessary for cellulose secretion. | Nature Communications

Fig. 5: Cellulase activity is necessary for cellulose secretion.

From: Insights into phosphoethanolamine cellulose synthesis and secretion across the Gram-negative cell envelope

Fig. 5

a Congo red (CR) fluorescence image of Ec macrocolonies expressing the indicating components as part of the Bcs complex. ‘All Bcs’ express the inner membrane complex (IMC) together with BcsZ and BcsC. ΔBcsZ: no BcsZ. b Carboxymethylcellulose digestion on agar plates using periplasmic Ec extracts. Cel9M and CMCax: Periplasmic extracts of cells expressing all Bcs components with BcsZ replaced by the indicated enzyme. BSA and A. niger: Controls with purified BSA or Aspergillus niger cellulase spotted on the agar plates. Cellulose digestion was imaged after CR staining, resulting in the observed plaques. c Evaluation of CR fluorescence exhibited by Ec macrocolonies expressing the indicated components as part of the Bcs complex. d Representative 2D class averages of BcsZ tetramers. e Model of the BcsZ tetramer shown as a semitransparent surface and cartoon, overlaid with the cellopentaose-bound crystal structure (PDB: 3QXQ, only cellopentaose is shown as ball-and-sticks in cyan and red). Two-fold symmetry axes are indicated by black ellipses. f Detailed views of the boxed regions in (e). CR and cellulase plate assays were repeated at least three times with similar results. Source data are provided as a Source Data File.

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