title: Concentration-dependent oligomerization of an alpha-helical antifreeze polypeptide makes it hyperactive.
abstract: A supersoluble 40-residue type I antifreeze protein (AFP) was discovered in a righteye flounder, the barfin plaice (bp). Unlike all other AFPs characterized to date, bpAFP transitions from moderately-active to hyperactive with increasing concentration. At sub-mM concentrations, bpAFP bound to pyramidal planes of ice to shape it into a bi-pyramidal hexagonal trapezohedron, similarly to the other moderately-active AFPs. At mM concentrations, bpAFP uniquely underwent further binding to the whole ice crystal surface including the basal planes. The latter caused a bursting ice crystal growth normal to c-axis, 3 °C of high thermal hysteresis, and alteration of an ice crystal into a smaller lemon-shaped morphology, all of which are well-known properties of hyperactive AFPs. Analytical ultracentrifugation showed this activity transition is associated with oligomerization to form tetramer, which might be the forerunner of a naturally occurring four-helix-bundle AFP in other flounders.
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Sheikh
authors.initials: S
authors.lastname: Mahatabuddin
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Hanada
authors.affiliation: Bioproduction Research Institute, ioproduction Research Institute and OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Nishimiya
authors.affiliation: Bioproduction Research Institute, ioproduction Research Institute and OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan.
authors.forename: Ai
authors.initials: A
authors.lastname: Miura
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.|Bioproduction Research Institute, ioproduction Research Institute and OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan.
authors.forename: Hidemasa
authors.initials: H
authors.lastname: Kondo
authors.affiliation: Protein Function Discovery Group and Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada.
authors.forename: Peter L
authors.initials: PL
authors.lastname: Davies
authors.affiliation: Graduate School of Life Science, Hokkaido University, Sapporo 060-0810, Japan.|Bioproduction Research Institute, ioproduction Research Institute and OPERANDO Open Innovation Laboratory, National Institute of Advanced Industrial Science and Technology (AIST), Sapporo 062-8517, Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Tsuda
mesh_terms: D000485:Allergens / Q000737:chemistry / Q000276:immunology; D000818:Animals; D021301:Antifreeze Proteins / Q000737:chemistry* / Q000276:immunology*; D029941:Fish Proteins / Q000737:chemistry / Q000276:immunology; D006863:Hydrogen-Ion Concentration; D010455:Peptides / Q000737:chemistry* / Q000276:immunology*; D000072756:Protein Conformation, alpha-Helical; D055503:Protein Multimerization; D055550:Protein Stability; D012995:Solubility
chemical_list: D000485:Allergens; D021301:Antifreeze Proteins; D029941:Fish Proteins; D010455:Peptides