Fig. 1: E. coli ρ with substitutions in the connector region form extended filaments.
From: Nucleotide-induced hyper-oligomerization inactivates transcription termination factor ρ
a Schematic diagram of ρ with key ATPase motifs, NusG-binding site, and positions of filament-inducing substitutions indicated. b Negatively stained in vitro filaments of ρ G150D•H8. Scale bar, 50 nm. Representative micrograph from three independent data acquisitions. c CryoEM reconstruction of G150D•H8 filaments. See Supplementary Figs. 1 and 2 for structural analysis of ρ G152D•H8 filaments. Left, 3D reconstruction, a locally filtered map; Right, model of the G150D•H8 filament in cartoon and semitransparent surface representation. d Comparison of WT and G150D hexamer geometries. The G150DF-ADP open ρ hexamer ring is extracted from the filament structure and compared to the untagged WT-ADP structure. Values of protomer-protomer distances and angles are derived from the draw_rotation axis script in Pymol. e–g Nucleotide-induced changes in the interaction network of the α5/α6 loop (residues 149-153 in orange) and helix α6 (residues 154–166 in orange) of G150D•H8 filament bound to ADP, untagged WT bound to ADP or ATP. Corresponding 3D reconstructions are shown in semitransparent surface representation. e F-ADP, ADP-bound ρ G150D•H8 filament (this study), (f) untagged WT hexamer bound to ADP (this study). g untagged WT hexamer bound to ATP (PDB ID: 6WA8). ADP and ATP nucleotides are shown in magenta. The partial unwinding of α6 repositions D156 close to the bound ADP in the F-ADP structure (e) enables the formation of additional interactions between D156 and T158 and D156 and ADP, respectively.
