The N-terminal domain of YopH is a compact structure composed of four alpha-helices and two beta-hairpins. Helices alpha-1 and alpha-3 are parallel to each other and antiparallel to helices alpha-2 and alpha-4. This domain targets YopH for secretion from the bacterium and translocation into eukaryotic cells, and has phosphotyrosyl peptide-binding activity, allowing for recognition of p130Cas and paxillin [1].

1: Structure of the N-terminal domain of Yersinia pestis YopH at 2.0 A resolution. Evdokimov AG, Tropea JE, Routzahn KM, Copeland TD, Waugh DS; Acta Crystallogr D Biol Crystallogr. 2001;57:793-799. PMID:11375498