HYDROPHOBINS AS FUSION PARTNERS FOR
PROTEIN EXPRESSION AND PURIFICATION
Class II hydrophobins HFBI and HFBII have been shown to
interact very strongly and efficiently with nonionic surfactants,
in a way that allows them to be purified in aqueous two-phase
systems.56 This opens up the potential for hydrophobins to be
used in recombinant protein purification. As a fusion tag,
hydrophobins can provide a simple, fast, efficient, and scalable
method for purifying recombinant proteins.57 The first use of
hydrophobins as a fusion tag for protein purification was
reported by Collen et al.,58 where they expressed and extracted
endoglucanase I-HFBI fusions from their original source, T.
reesei. The final yield of HFBI fusion proteins was 90% with a
sixfold enhancement in protein concentration. Subsequently,
cellular binding domain and green fluorescent protein have
been successfully expressed and purified in their active form
with high efficiency from T. reesei using the HFBI tag.57,59