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Bordetella adenylate cyclase toxin interacts with filamentous haemagglutinin to inhibit biofilm formation in vitro
Author(s) -
Hoffman Casandra,
Eby Joshua,
Gray Mary,
Heath Damron F.,
Melvin Jeffrey,
Cotter Peggy,
Hewlett Erik
Publication year - 2017
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.13551
Subject(s) - biofilm , adenylate cyclase toxin , biology , microbiology and biotechnology , bordetella pertussis , bordetella , cyclase , bordetella bronchiseptica , pertussis toxin , adenylate kinase , in vitro , bacteria , biochemistry , receptor , signal transduction , g protein , genetics
Summary Bordetella pertussis , the causative agent of whooping cough, secretes and releases adenylate cyclase toxin (ACT), which is a protein bacterial toxin that targets host cells and disarms immune defenses. ACT binds filamentous haemagglutinin (FHA), a surface‐displayed adhesin, and until now, the consequences of this interaction were unknown. A B. bronchiseptica mutant lacking ACT produced more biofilm than the parental strain; leading Irie et al . to propose the ACT‐FHA interaction could be responsible for biofilm inhibition. Here we characterize the physical interaction of ACT with FHA and provide evidence linking that interaction to inhibition of biofilm in vitro . Exogenous ACT inhibits biofilm formation in a concentration‐dependent manner and the N‐terminal catalytic domain of ACT (AC domain) is necessary and sufficient for this inhibitory effect. AC Domain interacts with the C‐terminal segment of FHA with ∼650 nM affinity. ACT does not inhibit biofilm formation by Bordetella lacking the mature C‐terminal domain (MCD), suggesting the direct interaction between AC domain and the MCD is required for the inhibitory effect. Additionally, AC domain disrupts preformed biofilm on abiotic surfaces. The demonstrated inhibition of biofilm formation by a host‐directed protein bacterial toxin represents a novel regulatory mechanism and identifies an unprecedented role for ACT.