(a) Structure of the WT (M113R/N139Q)6 (M113R/N139Q/L135C)1 mutant (cartoon view) showing the covalent attachment of cyclodextrin at position 135 (space filling model), the glutamines at residue 139, and the vertical distance between the secondary hydroxyls and the disulphide bond of the cyclodextrin. (b) β barrel structure showing the location of arginines (at position 113) and the cysteines in the mutants. Single letter standard amino acid code was used to describe the mutants, reprinted by permission from Nature Publishing Group: Nature Nanotechnology [59], copyright 2009.
