We report the first structural characterisation of histidine-rich glycoprotein, an important plasma adaptor protein following elucidation of the 1.93 Å X-ray crystal structure of the protein’s N2 domain (PDB: 4CCV). This region forms part of an important ligand interaction site on the molecule, that binds a range of molecules including the natural anti-coagultant, heparin. The structure, solved in collaboration with Prof. Jim Naismith’s laboratory revealed the presence of an S-glutathionyl adduct, which has implications for the control of angiogenesis. – Open access version in Europe PMC.