Fig. 1: Comparison of ordered configurations in the outer membrane, as imaged by AFM.

A When polymyxin was applied to purified outer membranes from MG1655 E. coli, ref. ¹ saw a hexagonal lattice with a spacing of 9.8 ± 3.9 nm. B Benn et al. ⁷ showed that the native, untreated outer membrane of living MG1655 E. coli was dominated by trimeric OMPs arranged in an imperfect hexagonal lattice, with a nearest-neighbour distance of 9.4 ± 2.1 nm. C Jaroslawski et al. ⁴ observed hexagonal arrangements of trimeric porins with a lattice constant of 8.1 ± 0.3 nm in purified outer membranes from R. Denitrificans. D Oestreicher et al. ⁶ showed hexagonal lattices (spacing 10.5 ± 1.7 nm) on the surface of living E. coli, which they attributed to trimeric OMPs. E Comparison of lattice-spacing distributions for polymyxin-induced hexagons¹ and for OMP lattices in native (untreated) MG1655 E. coli⁷, showing no significant difference by a two-sided t test with unequal variance (p = 0.16). Values are mean ± SD. Scale bar is 20 nm. Images A-D were reproduced from references as indicated, with permission.