Online Purchasing Account You are logged on as Guest. LoginRegister a New AccountShopping cart (Empty)
United States 

Bacterial model systems offers a robust method for screening amyloid inhibitors

Posted By Arun Kumar
Tags: Neuroscience

The function of proteins relies on their compact three-dimensional (3D) structures. Nascent polypeptides achieve their correct folding structure as dictated by their peptide sequence. The folding of proteins into their discrete 3D structures is the most fundamental example of biological self-assembly. Amyloid fibrils are thread like highly ordered protein aggregates with a core region formed by repetitive arrays of β-sheets oriented perpendicularly to the fibril axis. Aggregation of misfolded proteins into amyloid conformations that escape cellular quality-control mechanisms is a feature of wide range of debilitating diseases. The polypeptides adopt a common fold, cross-β-sheet which displays a signature “cross,” as seen in X-ray diffraction patterns. The conversion of peptides and proteins into aggregates is associated with several pathological conditions in humans, including Alzheimer’s disease (AD), Parkinson’s disease, transmissible sporadic encephalopathies cataract, and diabetes type II (Invernizzi et al., 2012). Alzheimer's disease is a fatal progressive neurodegenerative disorder and the underlying pathogenesis is the amyloid aggregation specifically β-amyloid peptide (Aβ) which accumulate in the brain as extracellular amyloid deposits. The aggregates exert cytotoxic effects by triggering a cascade of reactions resulting in neuronal dysfunction and dementia leading to death. Such disorders are predicted to cause a crisis in public health in the near future. Thus, there is an increasing need to understand the mechanism of protein misfolding and protein aggregation and this area has emerged as a high priority in biological and medical research which would lead to developing of effective therapies.

Methods of Amyloid detection

Many approaches exist to study amyloids in vitro, but the techniques available for the study of amyloid aggregation in cells are limited and non-specific. A gold standard in vitro method to screen for protein aggregation inhibitors employs a purified recombinant protein and Thioflavin-T (ThT) fluorometric assay to monitor aggregation. One of the limitations of in vitro evaluation of compounds against isolated protein targets is the failure to reproduce when assayed in vivo. However, fluorescence from ThT dyes have a spectral overlap of intrinsic fluorescence with cellular constituents such as Flavin and NADPH. An alternative is to use animal models to screen chemical libraries at early stages of drug discovery, but they are cost prohibitive and the assays are complex. Prokaryotic cells have recently emerged as suitable model systems to study mechanisms of amyloid formation and its inhibition.

Advantages of bacterial model system with PROTEOSTAT® dyes technology

Navarro and colleagues from University of Barcelona have demonstrated the successful application of bacterial systems as an effective and alternative system to screen for amyloid inhibitors on fluorescence spectroscopy and flow cytometry utilizing the advantages of novel red fluorescent Enzo’s PROTEOSTAT® dye. They expressed Aβ 40 and Aβ 42 in E.coli systems and established a screening protocol by benchmarking known amyloid inhibitors. Though bacterial systems do not recapitulate human multicellular systems, they have been shown to be of value in expression of aggregation-prone proteins. Relying on newly synthesized polypeptide mimics is physiologically closer than using a purified protein/peptide in in vitro aggregation assay. PROTEOSTAT® dye has a larger dynamic range and its fluorescence is not influenced by nucleic acids, its ability to discriminate between intracellular-amyloid like deposits and non-ordered aggregates. The combined use of PROTEOSTAT® with bacterial model systems has the potential to supplement the existing methods to screen small molecules to develop lead candidates for the treatment of amyloidogenic disease. Enzo Life Sciences offers comprehensive tools for advancing your research and detecting protein aggregates.

Share this TechNote

Never miss a new TechNote!

Receive our TechNotes as soon as they are published.

Follow Us!

comments powered by Disqus


  1. G. Invernizzi, Protein aggregation: mechanisms and functional consequences (2012) Int J Biochem Cell Biol. Sep; 44(9):1541-54. doi: 10.1016/j.biocel.2012.05.023. Epub 2012 Jun 17.
  2. S. Navarro A fast and specific method to screen for intracellular amyloid inhibitors using bacterial model systems (2016) Eur J Med Chem. 2016 Oct 4; 121:785-92. doi: 10.1016/j.ejmech.2015.10.044. Epub 2015 Oct 31.

Related Products

PROTEOSTAT® Aggresome detection kit  

Robust, quantitative detection of aggresomes relevant to the study of neurodegenerative disease, liver disease and  toxicology
Flow Cytometry, Fluorescence microscopy, Fluorescent detection | Print as PDF
ENZ-51035-0025 25 tests 142.00 USD
ENZ-51035-K100 100 tests 409.00 USD
Do you need bulk/larger quantities?

CYTO-ID® Autophagy detection kit 2.0 

A brighter and more photostable, no-transfection, quantitative assay for monitoring autophagy in live  cells
Flow Cytometry, Fluorescence microscopy, Fluorescent detection, HTS | Print as PDF
ENZ-KIT175-0050 50 tests 285.00 USD
ENZ-KIT175-0200 200 tests 603.00 USD
Do you need bulk/larger quantities?

p62 ELISA kit 

Highly validated, quantitative p62 ELISA kit available for autophagy research.
ELISA, Colorimetric detection | Print as PDF
ADI-900-212-0001 96 wells 697.00 USD
Do you need bulk/larger quantities?

Grp78/BiP ELISA kit 

High-sensitivity ELISA kit for quantifying both normal and upregulated levels of Grp78/BiP for unfolded protein response, cancer and neurodegenerative disease research.
ELISA, Colorimetric detection | Print as PDF
ADI-900-214-0001 96 wells 723.00 USD
Do you need bulk/larger quantities?

SCREEN-WELL® Autophagy library 

Structurally and mechanistically different compounds for studying the roles of pro- and anti-autophagic molecules in cells and in vitro applications.
HTS | Print as PDF
BML-2837-0100 1 Library 100 µl/well 1,386.00 USD
BML-2837-0500 1 Library 500 µl/well 3,559.00 USD
Do you need bulk/larger quantities?

LYSO-ID® Red detection kit (GFP-CERTIFIED®) 

Acidic organelle-selective dye for live cell staining of  lysosomes
Fluorescence microscopy, Fluorescent detection | Print as PDF
ENZ-51005-0100 100 tests 107.00 USD
ENZ-51005-500 500 tests 316.00 USD
Do you need bulk/larger quantities?

Proteasome ELISA kit 

The only commercially available kit for proteasome quantification.
ELISA | Print as PDF
BML-PW0575-0001 96 wells 558.00 USD
Do you need bulk/larger quantities?

Recommend this page