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Versatile Substrates and Probes for IgA1 Protease Activity
Author(s) -
Choudary Santosh K.,
Qiu Jiazhou,
Plaut Andrew G.,
Kritzer Joshua A.
Publication year - 2013
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201300281
Subject(s) - proteases , protease , microbiology and biotechnology , haemophilus influenzae , neisseria meningitidis , biology , immune system , bacteria , biochemistry , enzyme , immunology , antibiotics , genetics
Bacterial meningitis is a severe infectious disease with high mortality. Gram‐positive and Gram‐negative bacteria that cause meningitis secrete immunoglobulin A1 (IgA1) proteases to assist in mucosal colonization, invasion, and immune evasion. IgA1 proteases have unique selectivity, with few reported substrates other than IgA1 from human tissue. Here we describe the design, characterization, and application of peptide substrates for diverse IgA1 proteases from Neisseria , Haemophilus , and Streptococcus bacteria. IgA1 proteases from diverse strains showed unexpected selectivity profiles among peptide substrates derived from autoproteolytic sites. A fluorescence probe derived from one of these peptides was used to quantitate IgA1 protease activity in buffer and in human cerebrospinal fluid; it was able to detect recombinant Haemophilus influenzae type 1 IgA1 protease at less than 1 μg mL −1 . We also used the probe to establish the first high‐throughput screen for IgA1 protease inhibitors. This work provides tools that will help investigate the roles of IgA1 proteases in bacterial colonization, immune evasion, and infection.