Antioxidant activity and ACE-inhibitory of Class II hydrophobin from wild strain Trichoderma reesei

There are several possible uses of the Class II hydrophobin
HFBII in clinical applications. To fully understand and exploit this
potential however, the antioxidant activity and ACE-inhibitory potential
of this protein need to be better understood and have not been previously
reported. In this study, the Class II hydrophobin HFBII was produced by
the cultivation of wild type Trichoderma reesei. The crude hydrophobin
extract obtained from the fermentation process was purified using
reversed-phase liquid chromatography and the identity of the purified
HFBII verified by MALDI-TOF (molecular weight: 7.2 kDa). Subsequently the
antioxidant activity of different concentrations of HFBII (0.01-0.40
mg/mL) were determined. The results show that for HFBII concentrations of
0.04 mg/mL and upwards the protein significantly reduced the presence of
ABTS+ radicals in the medium, the IC50 value found to be 0.13 mg/mL.
Computational modeling highlighted the role of the amino acid residues
located in the conserved and exposed hydrophobic patch on the surface of
the HFBII molecule and the interactions with the aromatic rings of ABTS.
The ACE-inhibitory effect of HFBII was found to occur from 0.5 mg/mL and
upwards, making the combination of HFBII with strong ACE-inhibitors
attractive for use in the healthcare industry