Figure 1.

Structure of human serum albumin. (a) The molecule consists of a single polypeptide chain; about half of its length is an α-helix. The albumin structure comprises three homologous domains: I, marked in blue and cyan; II, green and yellow; III, orange and red. Each domain contains two subdomains, A and B, and two sites to bind hydrophobic molecules (Sudlow sites 1 and 2). (b) Sites for binding transition metal ions: N-terminal site, Cys34, and site А (multimetal binding site). Site B is not shown because its exact position is unknown.