Abstract
Filamentous fungi utilize small amphiphilic proteins called hydrophobins
in their adaptation to the environment. The hydrophobins are used to form
coatings on various fungal structures, lower the surface tension of water, and
to mediate surface attachment. Hydrophobins function through self-assembly at
interfaces, for example, at the air-water interface, and at fungal cellular
structures. Despite their high tendency to self assemble at interfaces,
hydrophobins can be very soluble in water. To understand the mechanism of
hydrophobin self-assembly, in this work, we have studied the behavior of two
Trichoderma reesei hydrophobins, HFBI and HFBII in aqueous solution. The main
methods used were Förster resonance energy transfer (FRET) and size
exclusion chromatography. A genetically engineered HFBI variant, NCys-HFBI,
was utilized for the site-specific labeling of dyes for the FRET experiments.
We observed the multimerization of HFBI in a concentration-dependent manner. A
change from monomers to tetramers was seen when the hydrophobin concentration
was increased. Interaction studies between HFBI and HFBII suggested that at
low concentrations homodimers are preferred, and at higher concentrations, the
heterotetramers of HFBI and HFBII are formed. In conclusion, the results
support the model where hydrophobins in aqueous solutions form multimers by
hydrophobic interactions. In contrast to micelles formed by detergents, the
hydrophobin multimers are defined in size and involve specific protein-protein
interactions.
Original language | English |
---|---|
Pages (from-to) | 8590 - 8598 |
Journal | Biochemistry |
Volume | 45 |
Issue number | 28 |
DOIs | |
Publication status | Published - 2006 |
MoE publication type | A1 Journal article-refereed |
Keywords
- hydrophobins
- filamentous fungi
- Trichoderma reesei
- coatings