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The salt‐sensitive structure and zinc inhibition of B orrelia burgdorferi protease BbHtrA
Author(s) -
Russell Theresa M.,
Tang Xiaoling,
Goldstein Jason M.,
Bagarozzi Dennis,
Johnson Barbara J. B.
Publication year - 2016
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13251
Subject(s) - proteases , biology , protease , serine protease , biochemistry , virulence , serine , borrelia burgdorferi , microbiology and biotechnology , enzyme , genetics , antibody , gene
Summary HtrA serine proteases are highly conserved and essential ATP ‐independent proteases with chaperone activity. Bacteria express a variable number of HtrA homologues that contribute to the virulence and pathogenicity of bacterial pathogens. Lyme disease spirochetes possess a single HtrA protease homologue, B orrelia burgdorferi HtrA ( BbHtrA ). Previous studies established that, like the human orthologue HtrA 1, BbHtrA is proteolytically active against numerous extracellular proteins in vitro . In this study, we utilized size exclusion chromatography and blue native polyacrylamide gel electrophoresis ( BN‐PAGE ) to demonstrate BbHtrA oligomeric structures that were substrate independent and salt sensitive. Examination of the influence of transition metals on the activity of BbHtrA revealed that this protease is inhibited by Zn 2+ > Cu 2+ > Mn 2+ . Extending this analysis to two other HtrA proteases, E . coli DegP and HtrA1, revealed that all three HtrA proteases were reversibly inhibited by ZnCl 2 at all micro molar concentrations examined. Commercial inhibitors for HtrA proteases are not available and physiologic HtrA inhibitors are unknown. Our observation of conserved zinc inhibition of HtrA proteases will facilitate structural and functional studies of additional members of this important class of proteases.