Abstract: Objective To obtain soluble expression of recombinant human heat shock transcription factor 5(rhHSF5) proteins and predict the structure of HSF5 bound to heat shock element. Methods The nucleotide sequence encoding the target gene was subcloned into expression vector pET-22b(+), followed by transformation into Escherichia coli BL21(DE3) strain and expression induction with IPTG. The rhHSF5 was purified using a Ni-NTA affinity column and gel filtration chromatography. A gel shift assay was carried out after the incubation of the purified rhHSF5 and an oligonucleotide containing a heat shock element. Structure prediction was done by means of homology modeling and molecular dynamics simulation. Results Soluble expression of rhHSF5 was achieved with high purity production. The purified rhHSF5 showed good binding activity with the heat shock element. A reasonable protein-DNA binding model was obtained. Conclusions The recombinant human HSF5 is produced in a soluble form with good yield and activity, which lays a solid foundation for mechanistic studies of this novel spermatogenesis regulator in the future.

Key words: spermatogenesis, heat shock transcription factor 5(HSF5), prokaryotic expression, soluble protein, structure prediction