VbhT is a bacterial Fic protein of the mammalian pathogen B. schoenbuchensis7,8. It is composed of an N-terminal FIC domain and a C-terminal BID domain. FIC domains are known to catalyse adenylylation (also called AMPylation). This entry represents VbhA, an antitoxin that binds FIC domain (filamentation induced by cyclic AMP) of VbhT and inhibits its activity. It inhibits the adenylylation activity of VbhT by positioning close to the putative ATP-binding site, hence competing with ATP binding [1].

1: Adenylylation control by intra- or intermolecular active-site obstruction in Fic proteins. Engel P, Goepfert A, Stanger FV, Harms A, Schmidt A, Schirmer T, Dehio C; Nature. 2012;482:107-110. PMID:22266942