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Anthrax toxin lethal factor contains a zinc metalloprotease consensus sequence which is required for lethal toxin activity
Author(s) -
Klimpel Kurt R.,
Arora Naveen,
Leppla Stephen H.
Publication year - 1994
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/j.1365-2958.1994.tb00500.x
Subject(s) - biology , toxin , metalloproteinase , anthrax toxin , sequence (biology) , consensus sequence , zinc , microbial toxins , microbiology and biotechnology , peptide sequence , genetics , matrix metalloproteinase , gene , recombinant dna , fusion protein , materials science , metallurgy
Summary Comparison of the anthrax toxin lethal factor (LF) amino acid sequence with sequences in the Swiss protein database revealed short regions of similarity with the consensus zinc‐binding site, HEXXH, that is characteristic of metalloproteases. Several protease inhibitors, including bestatin and captopril, prevented intoxication of macrophages by lethal toxin. LF was fully inactivated by site‐directed mutagenesis that substituted Ala for either of the residues (H‐686 and H‐690) implicated in zinc binding. Similarly, LF was inactivated by substitution of Cys for E‐687, which is thought to be an essential part of the catalytic site. In contrast, replacement of E‐720 and E‐721 with Ala had no effect on LF activity. LF bound 65 Zn both in solution and on protein blots. The 65 Zn binding was reduced for several of the LF mutants. These data suggest that anthrax toxin LF is a zinc metallopeptidase, the catalytic function of which is responsible for the lethal activity observed in cultured cells and in animals.