Figure 1. Ub chain conformations and ensemble FRET measurements.
(a-d) Distal (dark) and proximal (light) Ub moieties are shown in surface representation with hydrophobic patch (HP) residues (Leu8, Ile44, His68, Val70) in blue. N- and C-terminal Alexa dye attachment points are indicated. (a) Lys48-linked diUb derived from crystallographic and NMR analysis. (pdb-id 1aar8, 2pe99). (b) Alternative ‘compact’ Lys48-linked diUb (3aul11). (c) ‘Open’ Lys63-linked diUb (2jf513). (d) Met1-linked diUb from crystallography (2w9n13, 3axc14). (e) Schematic representation of FRET-labeled diUb assembly. See Supplementary Fig. 1 and Methods. (f) Uncorrected ensemble FRET measurements for diUb used in this study (see Supplementary Methods).