Crystal structure of a single‐chain trimer of human adiponectin globular domain

Adiponectin is increasingly recognized as a potential therapeutic agent for the treatment of diabetes and other metabolic diseases. It circulates in plasma as homotrimers and higher‐order oliogomers of homotrimers. To facilitate the production of active recombinant adiponectin as a therapeutic tool, we designed a single‐chain globular domain adiponectin (sc‐gAd) in which three monomer sequences are linked together in tandem to form one contiguous polypeptide. Here, we present the crystal structure of human sc‐gAd at 2.0 Å resolution. The structure reveals a similar trimeric topology to that of mouse gAd protein. Trimer formation is further rigidified by three calcium ions.