Functionally important pocket on the surface of dimeric Yersinia pestis SspA. The pocket is illustrated as ribbon diagrams (helices as spirals, b-strands as arrows, and loops as pipes) with the two subunits colored in cyan and orange, respectively. (Hansen, Gu, Li, Andrykovitch, Waugh, Jin, and Ji, J. Biol. Chem. 2005; 208:17380-17391. Abstract).