Outer Membrane Protease (OmpT)-based E. coli Sensing with Anionic Polythiophene and Unlabeled Peptide Substrate.

We report a simple and specific assay to detect as low as 1 CFU/mL of E. coli in water within 6 hours by targeting the bacteria's surface protease activity. The assay relies on polythiophene acetic acid (PTAA) as optical reporter and a short unlabeled peptide (LL37 FRRV ) previously optimized as substrate for OmpT, an outer membrane protease on E. coli . LL37 FRRV interacts with PTAA to enhance its fluorescence while also inducing the formation of a helical PTAA-LL37 FRRV construct, as confirmed by Circular Dichroism. However, in the presence of E. coli , LL37 FRRV is cleaved and can no longer affect PTAA's conformation and optical properties. This ability to distinguish between intact and cleaved peptide was investigated in detail using LL37 FRRV sequence variants.
PMID: 32618102 [PubMed - as supplied by publisher]

Source: Angewandte Chemie - July 1, 2020 Category: Chemistry Authors: Sinsinbar G, Gudlur S, Wood SE, Ammanath G, Yildiz HU, Alagappan P, Mrksich M, Liedberg B Tags: Angew Chem Int Ed Engl Source Type: research