Heat shock factor binding protein 1 (HSBP1) is a 76 amino acid protein that binds to heat shock factor 1(HSF1), which is a transcription factor involved in the HS response. HSBP1 is nuclear-localized and interacts with the active trimeric state of HSF1 to negatively regulated HSF1 DNA-binding activity. This protein was overexpressed in E.coli and was purified to apparent homogeneity by using conventional column chromatography techniques.