Fig. 4: Cryo-EM 3D structure of the G. haemolysans IgA1P complex with IgA1 with comparisons to the substrate-free state.
From: A substrate-induced gating mechanism is conserved among Gram-positive IgA1 metalloproteases
a 3D reconstruction of the G. haemolysans IgA1P-E1848A/IgA1 complex colored according to local resolution estimates (units in Å). b Density is shown from the single particle reconstruction along with the ribbon model of G. haemolysans IgA1P-E1848A and the bound IgA1. Each domain of the enzyme and IgA1 is colored as described in Fig. 1a, b. The IgA1 HC monomers are colored light blue and orange while the IgA1 LC fragments are colored navy blue. Only one IgA1-FAB fragment is visible in the density. c The full G. haemolysans IgA1P-E1848A/IgA1 complex model with each domain specifically delineated. d Structural comparison of the substrate-free G. haemolysans IgA1P (black) and the G. haemolysans IgA1P-E1848A/IgA1 complex (colored by domain). e The 4 Å conformational repositioning of the NTD2 domain and active site loops are shown between the substrate-free G. haemolysans IgA1P (black) and within its complex with IgA1 (colored) indicating the conformational change. Structural alignments of the substrate-free and substrate-bound complexes were conducted in Chimera using all domains of the metallo-IgA1P for a least-squares RMSD superposition.
