Crystal Packing Differences as a Key Factor for Stabilization of the N-Terminal Fragment of the Human HINT1 Protein

Histidine triad nucleotide-binding protein 1 (HINT1) is the oldest and most widely distributed branch of the histidine triad superfamily of proteins. The HINT1 protein plays an important role in various biological processes and has been found in many species. Here we report the first nearly complete structure of the human HINT1 protein at 1.43 Å resolution obtained from a crystal of the P212121 orthorhombic space group. The final structure has an Rcryst = 22.4% (Rfree = 27.7%) and contains a fragment of the N-terminal part that was not determined in the previously deposited structures. In addition, selective binding of the L-malate ion was detected, which had not been observed previously.