Diversity, biogenesis and function of microbial amyloids

Blanco, Luz P.; Evans, Margery L.; Smith, Daniel R.; Badtke, Matthew P.; Chapman, Matthew R.

doi:10.1016/j.tim.2011.11.005

Cited by 285 publications

(269 citation statements)

References 87 publications

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“…Escherichia coli, Salmonella spp., and many other Enterobacteriaceae produce functional amyloid fibers, called curli, on their surfaces (3)(4)(5)(6) that are involved in cell adherence, invasion, host colonization, and biofilm formation (6)(7)(8)(9)(10)(11). Curli fibers make up the primary proteinaceous component of the extracellular matrix in pellicle biofilm, a subset of biofilms formed by the cystitis uropathogenic E. coli isolate UTI89 (12).…”

mentioning

confidence: 99%

Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation

Krezel

Cusumano

Pinkner

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Curli, consisting primarily of major structural subunit CsgA, are functional amyloids produced on the surface of Escherichia coli, as well as many other enteric bacteria, and are involved in cell colonization and biofilm formation. CsgE is a periplasmic accessory protein that plays a crucial role in curli biogenesis. CsgE binds to both CsgA and the nonameric pore protein CsgG. The CsgG-CsgE complex is the curli secretion channel and is essential for the formation of the curli fibril in vivo. To better understand the role of CsgE in curli formation, we have determined the solution NMR structure of a double mutant of CsgE (W48A/F79A) that appears to be similar to the wild-type (WT) protein in overall structure and function but does not form mixed oligomers at NMR concentrations similar to the WT. The well-converged structure of this mutant has a core scaffold composed of a layer of two α-helices and a layer of three-stranded antiparallel β-sheet with flexible N and C termini. The structure of CsgE fits well into the cryoelectron microscopy density map of the CsgG-CsgE complex. We highlight a striking feature of the electrostatic potential surface in CsgE structure and present an assembly model of the CsgG-CsgE complex. We suggest a structural mechanism of the interaction between CsgE and CsgA. Understanding curli formation can provide the information necessary to develop treatments and therapeutic agents for biofilm-related infections and may benefit the prevention and treatment of amyloid diseases. CsgE could establish a paradigm for the regulation of amyloidogenesis because of its unique role in curli formation.biofilm formation | intrinsically disordered protein | aggregation | protein-protein interaction | CsgG

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mentioning

confidence: 99%

Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation

Krezel

Cusumano

Pinkner

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Although the fibers formed by different proteins have similar structures, the functionality of these fibers can be diverse. The recent discovery that bacterial amyloid fibrils have specific functions and as such, are a productive part of the microorganism biology has led to the coining of the term "functional amyloids" (13,34,35,36,37). The best-characterized bacterial amyloid is curli, whose formation in vivo requires at least six specific proteins dedicated to curli biogenesis (38).…”

Section: Discussionmentioning

confidence: 99%

Microcin E492 Amyloid Formation Is Retarded by Posttranslational Modification

Marcoleta

Marín

Mercado

et al. 2013

Journal of Bacteriology

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b Microcin E492, a channel-forming bacteriocin with the ability to form amyloid fibers, is exported as a mixture of two forms: unmodified (inactive) and posttranslationally modified at the C terminus with a salmochelin-like molecule, which is an essential modification for conferring antibacterial activity. During the stationary phase, the unmodified form accumulates because expression of the maturation genes mceIJ is turned off, and microcin E492 is rapidly inactivated. The aim of this work was to demonstrate that the increase in the proportion of unmodified microcin E492 augments the ability of this bacteriocin to form amyloid fibers, which in turn decreases antibacterial activity. To this end, strains with altered proportions of the two forms were constructed. The increase in the expression of the maturation genes augmented the antibacterial activity during all growth phases and delayed the loss of activity in the stationary phase, while the ability to form amyloid fibers was markedly reduced. Conversely, a higher expression of microcin E492 protein produced concomitant decreases in the levels of the modified form and in antibacterial activity and a substantial increase in the ability to form amyloid fibers. The same morphology for these fibers, including those formed by only the unmodified version, was observed. Moreover, seeds formed using exclusively the nonmodified form were remarkably more efficient in amyloid formation with a shorter lag phase, indicating that the nucleation process is probably improved. Unmodified microcin E492 incorporation into amyloid fibers was kinetically more efficient than the modified form, probably due to the existence of a conformation that favors this process.

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“…curli), biosurfactants, and other macromolecules, with the composition depending on the cell strains and their environment [11,34]. Its cohesive properties derive from chemical and strong physical intermolecular bonds (e.g.…”

Section: Molecular Origins Of Biofilm Mechanicsmentioning

confidence: 99%

Biomechanical Analysis of Infectious Biofilms

Head

2016

Biophysics of Infection

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The removal of infectious biofilms from tissues or implanted devices and their transmission through fluid transport systems depends in part of the mechanical properties of their polymeric matrix. Linking the various physical and chemical microscopic interactions to macroscopic deformation and failure modes promises to unveil design principles for novel therapeutic strategies targeting biofilm eradication, and provide a predictive capability to accelerate the development of devices, water lines etc. that minimise microbial dispersal. Here our current understanding of biofilm mechanics is appraised from the perspective of biophysics, with an emphasis on constitutive modelling that has been highly successful in soft matter. Fitting rheometric data to viscoelastic models has quantified linear and non-linear stress relaxation mechanisms, how they vary between species and environments, and how candidate chemical treatments alter the mechanical response. The rich interplay between growth, mechanics and hydrodynamics is just becoming amenable to computational modelling and promises to provide unprecedented characterisation of infectious biofilms in their native state.

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Diversity, biogenesis and function of microbial amyloids

Cited by 285 publications

References 87 publications

Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation

Solution NMR structure of CsgE: Structural insights into a chaperone and regulator protein important for functional amyloid formation

Microcin E492 Amyloid Formation Is Retarded by Posttranslational Modification

Biomechanical Analysis of Infectious Biofilms

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