This family includes envelope integrity protein A (EipA), a protein required for B. abortus envelope stress resistance and infection. It's gene expression is directly activated by CtrA which binds to the promoter region. eipA encodes a soluble periplasmic protein that adopts an unusual eight-stranded beta-barrel fold [1].

1: Periplasmic protein EipA determines envelope stress resistance and virulence in Brucella abortus. Herrou J, Willett JW, Fiebig A, Varesio LM, Czyz DM, Cheng JX, Ultee E, Briegel A, Bigelow L, Babnigg G, Kim Y, Crosson S; Mol Microbiol. 2018; [Epub ahead of print] PMID:30536925