title: Ice and anti-nucleating activities of an ice-binding protein from the annual grass, Brachypodium distachyon.
abstract: Plants exposed to sub-zero temperatures face unique challenges that threaten their survival. The growth of ice crystals in the extracellular space can cause cellular dehydration, plasma membrane rupture and eventual cell death. Additionally, some pathogenic bacteria cause tissue damage by initiating ice crystal growth at high sub-zero temperatures through the use of ice-nucleating proteins (INPs), presumably to access nutrients from lysed cells. An annual species of brome grass, Brachypodium distachyon (Bd), produces an ice-binding protein (IBP) that shapes ice with a modest depression of the freezing point (~0.1 °C at 1 mg/mL), but high ice-recrystallization inhibition (IRI) activity, allowing ice crystals to remain small at near melting temperatures. This IBP, known as BdIRI, is unlike other characterized IBPs with a single ice-binding face, as mutational analysis indicates that BdIRI adsorbs to ice on two faces. BdIRI also dramatically attenuates the nucleation of ice by bacterial INPs (up to -2.26 °C). This 'anti-nucleating' activity is significantly higher than previously documented for any IBP.
authors.affiliation: Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
authors.forename: Melissa
authors.identifier: 0000-0002-5564-9646
authors.initials: M
authors.lastname: Bredow
authors.affiliation: Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
authors.forename: Heather E
authors.initials: HE
authors.lastname: Tomalty
authors.affiliation: Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Smith
authors.affiliation: Department of Biology, Queen's University, Kingston, Ontario, K7L 3N6, Canada.|Department of Biomedical and Molecular Sciences, and School of Environmental Studies, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
authors.forename: Virginia K
authors.initials: VK
authors.lastname: Walker
mesh_terms: D000064:Acclimatization; D021301:Antifreeze Proteins / Q000235:genetics / Q000378:metabolism*; D058431:Brachypodium / Q000235:genetics / Q000502:physiology*; D005615:Freezing; D007053:Ice; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D044366:Transition Temperature
chemical_list: D021301:Antifreeze Proteins; D007053:Ice; D010940:Plant Proteins
keywords: Brachypodium; cold; freeze tolerance; ice nucleation; pathogens