title: Identification and characterization of gushing-active hydrophobins from Fusarium graminearum and related species.
abstract: Fungal infection of barley and malt, particularly by the Fusarium species, is a direct cause of spontaneous overfoaming of beer, referred to as gushing. We have shown previously that small fungal proteins, hydrophobins, act as gushing-inducing factors in beer. The aim of our present study was to isolate and characterize hydrophobins from a gushing-active fungus, Fusarium graminearum (teleomorph Gibberella zeae) and related species. We generated profile hidden Markov models (profile HMMs) for the hydrophobin classes Ia, Ib and II from the multiple sequence alignments of their known members available in public domain databases. We searched the published Fusarium graminearum genome with the Markov models. The best matching sequences and the corresponding genes were isolated from F. graminearum and the related species F. culmorum and F. poae by PCR and characterized. One each of the putative F. graminearum and F. poae hydrophobin genes were expressed in the heterologous host Trichoderma reesei. The proteins corresponding to the genes were purified and identified as hydrophobins and named GzHYD5 and FpHYD5, respectively. Concentrations of 0.003 ppm of these hydrophobins were observed to induce vigorous beer gushing.
authors.affiliation: VTT Technical Research Centre of Finland, Helsinki, Finland. tuija.sarlin@vtt.fi
authors.forename: Tuija
authors.initials: T
authors.lastname: Sarlin
authors.forename: Teemu
authors.initials: T
authors.lastname: Kivioja
authors.forename: Nisse
authors.initials: N
authors.lastname: Kalkkinen
authors.forename: Markus B
authors.initials: MB
authors.lastname: Linder
authors.forename: Tiina
authors.initials: T
authors.lastname: Nakari-Setälä
mesh_terms: D000595:Amino Acid Sequence; D001515:Beer / Q000382:microbiology*; D003001:Cloning, Molecular; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D005670:Fusarium / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D008390:Markov Chains; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; D011994:Recombinant Proteins