Fig. 4
From: The structure of a β2-microglobulin fibril suggests a molecular basis for its amyloid polymorphism
The structure of β2m in its native and fibrillar states. The strands of native β2m (a) are labelled A–G, and those of the fibrillar β2m subunit (b) are labelled 1–6. Each structure is identically coloured from N-terminus (blue) to C-terminus (red). Residues in the N-terminal (Strand A, blue) and C-terminal (Strand G, red) strands of the native structure are disordered and not present in the core of the fibrillar subunit. c β-strands in the fibrillar subunits coincide remarkably well to β-strands B–F in the native fold, although the B and C strands are shorter. d The N- and C-terminal regions of the β2m fibril are disordered. The atomic model for the ordered portion of the fibril superimposed over slices through the EM density perpendicular to the fibril axis at varying contour levels, showing less-ordered regions that must contain the N- and C-terminal residues. The grey density is at a contour level of 0.04, followed by a contour at 0.035 (blue), 0.030 (green), and 0.025 (red), which show the position of weaker, less-ordered density
