title: Structure of haze forming proteins in white wines: Vitis vinifera thaumatin-like proteins.
abstract: Grape thaumatin-like proteins (TLPs) play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential. The three TLPs have very similar structures despite belonging to two different classes (F2/4JRU is a thaumatin-like protein while I/4L5H and H2/4MBT are VVTL1), and having different unfolding temperatures (56 vs. 62°C), with protein F2/4JRU being heat unstable and forming haze, while I/4L5H does not. These differences in properties are attributable to the conformation of a single loop and the amino acid composition of its flanking regions.
authors.affiliation: The Australian Wine Research Institute, Adelaide, South Australia, Australia.
authors.forename: Matteo
authors.initials: M
authors.lastname: Marangon
authors.affiliation: The Australian Wine Research Institute, Adelaide, South Australia, Australia; School of Botany, University of Melbourne, Victoria, Australia.
authors.forename: Steven C
authors.initials: SC
authors.lastname: Van Sluyter
authors.affiliation: The Australian Wine Research Institute, Adelaide, South Australia, Australia.
authors.forename: Elizabeth J
authors.initials: EJ
authors.lastname: Waters
authors.affiliation: School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia.
authors.forename: Robert I
authors.initials: RI
authors.lastname: Menz
mesh_terms: D000596:Amino Acids / Q000235:genetics; D002688:Chitinases / Q000737:chemistry; D054884:Host-Pathogen Interactions / Q000235:genetics*; D010940:Plant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D027843:Vitis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014920:Wine
chemical_list: D000596:Amino Acids; D010940:Plant Proteins; C003427:thaumatin protein, plant; D002688:Chitinases