Cloning, prokaryotic expression,purification and sequence analysis of 20S proteasome subunit gene from T.harzianum

The gene encoding the 20S proteasome subunit（PR29） was cloned from cDNA library of Trichoderma harzianum and expressed in Escherichia coli BL21 （D3） using a pET-28a expression system. The molecular weight of the protein was found to be approximately 29 kDa, as estimated by SDS-PAGE on gels. The target protein was insoluble when induced at 22℃ with 0.4 mmol/L IPTG, while dissoluble if induced at 37℃ with 0.8mmoL/L IPTG. The expressed product was purified through Ni-magnetic beads His Bind. The purity of the fusion protein reached above 80%. The entire eDNA sequence consisted of 1094 bp with 173 and 135 bp in 5＇ and 3＇ untranslated regions respectively. The gene encoding 261 amino acids has no signal peptide sequence. These results could provide a basis for validating the func-tions of PR29. It also provided a preliminary indication for further study of the mechanism and function of proteasome, and more information of proteasome mechanism in T.harzianum could be obtained.

Cloning, prokaryotic expression, purification and sequence analysis of 20S proteasome subunit gene from T. harzianum

The gene encoding the 20S proteasome subunit (PR29) was cloned from cDNA library of Trichoderma harzianum and expressed in Escherichia coll BL21 (D3) using a pET-28a expression system. The molecular weight of the protein was found to be approximately 29 kDa, as estimated by SDS-PAGE on gels. The target protein was insoluble when induced at 22 Cwith 0.4 mmol/ L IPTG, while dissoluble if induced at 37℃ with 0.8mmol/ L IPTG. The expressed product was purified through Ni-magnetic beads His Bind. The purity of the fusion protein reached above 80% .The entire cDNA sequence consisted of 1094 bp with 173 and 135 bp in 5' and 3' untranslated regions respectively. The gene encoding 261 amino acids has no signal peptide sequence. These results could provide a basis for validating the functions of PR29. It also provided a preliminary indication for further study of the mechanism and function of proteasome, and more information of proteasome mechanism in T. harzianum could be obtained.