Premium
Outer‐Membrane Protease (OmpT) Based E. coli Sensing with Anionic Polythiophene and Unlabeled Peptide Substrate
Author(s) -
Sinsinbar Gaurav,
Gudlur Sushanth,
Wood Sarah E.,
Ammanath Gopal,
Yildiz Hakan U.,
Alagappan Palaniappan,
Mrksich Milan,
Liedberg Bo
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.202008444
Subject(s) - circular dichroism , protease , bacterial outer membrane , peptide , escherichia coli , chemistry , linker , substrate (aquarium) , biochemistry , combinatorial chemistry , enzyme , biophysics , biology , ecology , computer science , gene , operating system
E. coli and Salmonella are two of the most common bacterial pathogens involved in foodborne and waterborne related deaths. Hence, it is critical to develop rapid and sensitive detection strategies for near‐outbreak applications. Reported is a simple and specific assay to detect as low as 1 CFU mL −1 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 an optical reporter and a short unlabeled peptide (LL37 FRRV ) previously optimized as a 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 the conformations and optical properties of PTAA. This ability to distinguish between an intact and cleaved peptide was investigated in detail using LL37 FRRV sequence variants.