Interaction and comparison of a class I hydrophobin from Schizophyllum commune and class II hydrophobins from Trichoderma reesei
ABSTRACT Hydrophobins fulfill a wide spectrum of functions in fungal growth and development. These proteins self-assemble at hydrophilic-hydrophobic interfaces into amphipathic membranes. Hydrophobins are divided into two classes based on their hydropathy patterns and solubility. We show here that the properties of the class II hydrophobins HFBI and HFBII of Trichoderma reesei differ from those of the class I hydrophobin SC3 of Schizophyllum commune. In contrast to SC3, self-assembly of HFBI and HFBII at the water-air interface was neither accompanied by a change in secondary structure nor by a change in ultrastructure. Moreover, maximal lowering of the water surface tension was obtained instantly or took several minutes in the case of HFBII and HFBI, respectively. In contrast, it took several hours in the case of SC3. Oil emulsions prepared with HFBI and SC3 were more stable than those of HFBII, and HFBI and SC3 also interacted more strongly with the hydrophobic Teflon surface making it wettable. Yet, the HFBI coating did not resist treatment with hot detergent, while that of SC3 remained unaffected. Interaction of all the hydrophobins with Teflon was accompanied with a change in the circular dichroism spectra, indicating the formation of an alpha-helical structure. HFBI and HFBII did not affect self-assembly of the class I hydrophobin SC3 of S. commune and vice versa. However, precipitation of SC3 was reduced by the class II hydrophobins, indicating interaction between the assemblies of both classes of hydrophobins.
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ABSTRACT: Hydrophobins are proteins exclusively produced by filamentous fungi. They self-assemble at hydrophilic-hydrophobic interfaces into an amphipathic film. This protein film renders hydrophobic surfaces of gas bubbles, liquids, or solid materials wettable, while hydrophilic surfaces can be turned hydrophobic. These properties, among others, make hydrophobins of interest for medical and technical applications. For instance, hydrophobins can be used to disperse hydrophobic materials; to stabilize foam in food products; and to immobilize enzymes, peptides, antibodies, cells, and anorganic molecules on surfaces. At the same time, they may be used to prevent binding of molecules. Furthermore, hydrophobins have therapeutic value as immunomodulators and can been used to produce recombinant proteins.Applied Microbiology and Biotechnology 01/2015; 99(4). DOI:10.1007/s00253-014-6319-x · 3.81 Impact Factor
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ABSTRACT: Production and purification of hydrophobin HFBII has recently been the subject of intensive research, but the yield of production needs to be further improved for a generic use of this molecule at industrial scale. In a first step, the influence of different carbon sources on the growth of Trichoderma reesei and the production of HFBII was investigated. The optimum productivity was obtained by using 40 g/L lactose. Carbon starvation and excretion of extracellular enzyme were determined as two main conditions for the production of HFBII. In the second phase, and according to the physiological mechanisms observed during the screening phase, a bioreactor set up has been designed and two modes of cultures have been investigated, i.e. the classical submerged fermentation and a fungal biofilm reactor. In this last set-up, the broth is continuously recirculated on a metal packing exhibiting a high specific surface. In this case, the fungal biomass was mainly attached to the metal packing, leading to a simplification of downstream processing scheme. More importantly, the HFBII concentration increased up to 48.6 +/- 6.2 mg/L which was 1.8 times higher in this reactor configuration and faster than the submerged culture. X-ray tomography analysis shows that the biofilm overgrowth occurs when successive cultures are performed on the same packing. However, this phenomenon has no significant influence on the yield of HFBII, suggesting that this process could be operated in continuous mode. Protein hydrolysis during stationary phase was observed by MALDI-TOF analysis according to the removal of the last amino acid from the structure of HFBII after 48 h from the beginning of fermentation in biofilm reactor. Hopefully this modification does not lead to alternation of the main physicochemical properties of HFBII.Biochemical Engineering Journal 07/2014; 88. DOI:10.1016/j.bej.2014.05.001 · 2.37 Impact Factor
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ABSTRACT: Hydrophobins are morphogenetic, small secreted hydrophobic fungal proteins produced in response to changing development and environmental conditions. These proteins are important in the interaction between certain fungi and their hosts. In mutualistic ectomycorrhizal fungi several hydrophobins form a subclass of mycorrhizal-induced small secreted proteins that are likely to be critical in the formation of the symbiotic interface with host root cells. In this study, two genomes of the ectomycorrhizal basidiomycete Laccaria bicolor strains S238N-H82 (from North America) and 81306 (from Europe) were surveyed to construct a comprehensive genome-wide inventory of hydrophobins and to explore their characteristics and roles during host colonization. The S238N-H82 L. bicolor hydrophobin gene family is composed of 12 genes while the 81306 strain encodes nine hydrophobins, all corresponding to class I hydrophobins. The three extra hydrophobin genes encoded by the S238N-H82 genome likely arose via gene duplication and are bordered by transposon rich regions. Expression profiles of the hydrophobin genes of L. bicolor varied greatly depending on life stage (e.g. free living mycelium vs. root colonization) and on the host root environment. We conclude from this study that the complex diversity and range of expression profiles of the Laccaria hydrophobin multi-gene family have likely been a selective advantage for this mutualist in colonizing a wide range of host plants.Fungal Genetics and Biology 03/2012; 49(3):199-209. DOI:10.1016/j.fgb.2012.01.002 · 3.26 Impact Factor