Aromatic-participant interactions are essential for disulfide-bond-based trimerization in human heat shock transcription factor 1

The functional significance of three conserved aromatic amino acids (Trp37, Tyr60, and Phe104) for heat shock transcription factor 1 (HSF1) trimerization is demonstrated. An intramolecular interaction between Tyr60 and [alpha]-helix 1 in the DNA-binding domain and intermolecular aromatic-aromatic interaction between the Trp37 and Phe104 facilitated the formation of intermolecular disulfide bonds, leading to the heat-induced HSF1 trimerization.