Format

Send to

Choose Destination
J Mol Biol. 2013 Nov 15;425(22):4286-94. doi: 10.1016/j.jmb.2013.06.022. Epub 2013 Jul 1.

Sum of the parts: composition and architecture of the bacterial extracellular matrix.

Author information

1
Department of Chemistry, Stanford University, Stanford, CA 94305, USA.

Abstract

Bacterial biofilms are complex multicellular assemblies that exhibit resistance to antibiotics and contribute to the pathogenesis of serious and chronic infectious diseases. New approaches and quantitative data are needed to define the molecular composition of bacterial biofilms. Escherichia coli biofilms are known to contain polysaccharides and functional amyloid fibers termed curli, yet accurate determinations of biofilm composition at the molecular level have been elusive. The ability to define the composition of the extracellular matrix (ECM) is crucial for the elucidation of structure-function relationships that will aid the development of chemical strategies to disrupt biofilms. We have developed an approach that integrates non-perturbative preparation of the ECM with electron microscopy, biochemistry, and solid-state NMR spectroscopy to define the chemical composition of the intact and insoluble ECM of a clinically important pathogenic bacterium--uropathogenic E. coli. Our data permitted a sum-of-all-the-parts analysis. Electron microscopy revealed supramolecular shell-like structures that encapsulated single cells and enmeshed the bacterial community. Biochemical and solid-state NMR measurements of the matrix and constitutive parts established that the matrix is composed of two major components, curli and cellulose, each in a quantifiable amount. This approach to quantifying the matrix composition is widely applicable to other organisms and to examining the influence of biofilm inhibitors. Collectively, our NMR spectra and the electron micrographs of the purified ECM inspire us to consider the biofilm matrix not as an undefined slime, but as an assembly of polymers with a defined composition and architecture.

KEYWORDS:

CPMAS; ECM; MAS; NMR; REDOR; biofilm; cross-polarization magic-angle spinning; curli; extracellular matrix; functional amyloid; magic-angle spinning; rotational-echo double-resonance

PMID:
23827139
PMCID:
PMC3812305
DOI:
10.1016/j.jmb.2013.06.022
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Elsevier Science Icon for PubMed Central
Loading ...
Support Center