Fig. 2 |. Cryo-EM structure of Bl_Man38A as an archetypal model of the three bifidobacterial α-mannosidases.
a, Tetrameric arrangement of Bl_Man38A colored by chain, except for chain A, which was colored by domains using the color scheme represented in b and c. b, Scheme showing the domain organization. c, Cartoon representation of one protomer of the tetramer colored by domain. d, Conserved metal ion-binding site that composes the −1 subsite complexed with a Zn2+ ion. e, Interactions with a mannose at the −1 subsite of the Bl_Man38AD387A mutant. f, Superposition of residues that compose the −1 subsite for wide-type structures of Bl_Man38A (carbons are in cyan), Bl_Man38B (carbons are in white) and Bl_Man38C (carbons are in dark gray). The corresponding figures for the protomers of Bl_Man38B and Bl_Man38C are presented in Supplementary Figs. 13 and 14.