Binding interactions made by dansylated amino acids (DanN, DanE, DanR) in drug site 1 (sub-domain IIA) of HSA in the absence and presence of fatty acid. (a) Binding of DanN (coloured by atom type as in Fig. 1b). Hydrogen bonds are shown as dotted cyan lines. (b) Comparison of the binding of DanN and warfarin (Petitpas et al., 2001). The view is rotated slightly to the left compared to panel a; the polypeptide containing Y150 has been removed for clarity. (c) Binding of DanN to HSA in the presence of myristate (shown as CPK spheres, coloured by atom type: carbon – grey and oxygen – red). (d) Comparison of the binding of DanN, DanE and DanR to HSA–myristate. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Location of binding sites for dansylated amino acids determined by X-ray crystallography. (a) Simulated annealing F_o − F_c omit map (contoured at 3σ) showing DanF bound to drug site 2 in sub-domain IIIA. DanF is shown in a stick representation with atoms coloured by atom-type: C – purple; O – red; and N – blue. Sub-domain IIIA is shown in a ribbon representation (blue). Selected protein side-chains are shown as sticks, with carbon atoms coloured grey. (b) Overview of DanN bound to drug sites 1 and 2 in HSA. The ligands are shown in a stick representation with a semi-transparent molecular surface. The protein secondary structure is shown coloured by sub-domain. This colour scheme is maintained throughout. (c) Overview of DanN bound to sub-domains IIA and IB in HSA–myristate. The seven fatty acid binding sites on the protein are labelled FA1–FA7. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Binding interactions made by dansylated amino acids (DanSRC, DanNV, DanF and DanN) in drug site 2 (sub-domain IIIA) of HSA. (a) Binding of DanF (coloured by atom type as in Fig. 1a). Hydrogen bonds are shown as dotted cyan lines. (b) Comparison of the binding of DanF and indoxyl sulphate (IDS) Ghuman et al., 2005; carbon atoms in IDS are coloured dark yellow. (c) Comparison of the binding of DanF, DanNV and DanSRC to drug site 2 of HSA. (d) Comparison of the binding of DanF and DanN to drug site 2 of HSA. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)