Cryo-EM structure of the P1-Fab(P1/MCA4) complex [Dataset]

a) Ribbon representations, with three 90° apart views, of the complex between the ectodomain of P1 (brown) and the Fab fragment of Mab P1/MCA4 (light and heavy chains in blue and green, respectively). Insets indicate the main interactions between P1 and the Fab. The epitope is located in the C-domain of P1 closed to the mycoplasma membrane, which is also displayed as a reference. b) Two views of the Fab(P1/MCA4) (shown in green) and the extracellular region of the Nap, with P1 (brown) and P40/P90 (pink transparent). In the “open” conformation of the Nap (left panel) the P1/MCA4 epitope, buried at the center of the Nap, is totally inaccessible to antibodies and a Fab placed there would catastrophically clash with the adhesins. Therefore, to expose the P1/MCA4 epitope the C-domain of P1 has to experience an important rearrangement (right panel).