Fig. 1: MreCPa self-associates in vitro into bundles, tubes, and antiparallel filaments.
From: Self-association of MreC as a regulatory signal in bacterial cell wall elongation
a Domain scheme of selected MreC variants. β-barrels were aligned to the ‘butterfly’ region of MreC from P. aeruginosa (the β-sandwich core). b SV-AUC sedimentation curves for MreCPa, MreCEc, and MreCAb. All three variants display very large s values in AUC, with MreC from P. aeruginosa showing the highest propensity to generate the largest oligomeric forms. Inset curves display different sedimentation ranges, with 0–50 (s) indicating the presence of oligomers from the three species, and the 200–700 (s) range indicating a pronounced peak for MreCPa only. c Negative stain electron micrographs showing higher order structures formed by recombinant MreCPa which were suitable for cryo-EM studies. The bars indicate 50 nm. During this study, over 300 images were made, and more than 20 grids prepared in total. d The same sample shown by cryo-EM reveals forms with diameters of 180 and 220 Å, and is a representative of images obtained from three different cryo-EM experiments, with 4 grids being prepared for the one highlighted here. e, f MreCPa self-associates into tubes formed by six sets of antiparallel protofilaments. Individual protofilaments are shown in cyan and green. Inner and outer tube dimensions correspond to 150 Å and 280 Å, respectively. The tubular structures shown above represent the most stable in vitro form that allowed structural characterization. Source data are provided as a Source Data file.
