title: Long-range protein-water dynamics in hyperactive insect antifreeze proteins.
abstract: Antifreeze proteins (AFPs) are specific proteins that are able to lower the freezing point of aqueous solutions relative to the melting point. Hyperactive AFPs, identified in insects, have an especially high ability to depress the freezing point by far exceeding the abilities of other AFPs. In previous studies, we postulated that the activity of AFPs can be attributed to two distinct molecular mechanisms: (i) short-range direct interaction of the protein surface with the growing ice face and (ii) long-range interaction by protein-induced water dynamics extending up to 20 Å from the protein surface. In the present paper, we combine terahertz spectroscopy and molecular simulations to prove that long-range protein-water interactions make essential contributions to the high antifreeze activity of insect AFPs from the beetle Dendroides canadensis. We also support our hypothesis by studying the effect of the addition of the osmolyte sodium citrate.
authors.affiliation: Lehrstuhl für Physikalische Chemie II,  Ruhr Universität, 44801 Bochum,  Germany.
authors.forename: Konrad
authors.initials: K
authors.lastname: Meister
authors.forename: Simon
authors.initials: S
authors.lastname: Ebbinghaus
authors.forename: Yao
authors.initials: Y
authors.lastname: Xu
authors.forename: John G
authors.initials: JG
authors.lastname: Duman
authors.forename: Arthur
authors.initials: A
authors.lastname: DeVries
authors.forename: Martin
authors.initials: M
authors.lastname: Gruebele
authors.forename: David M
authors.initials: DM
authors.lastname: Leitner
authors.forename: Martina
authors.initials: M
authors.lastname: Havenith
mesh_terms: D000818:Animals; D021301:Antifreeze Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002951:Citrates / Q000737:chemistry; D001517:Coleoptera / Q000235:genetics / Q000378:metabolism; D003198:Computer Simulation; D019476:Insect Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D000077559:Sodium Citrate; D013057:Spectrum Analysis / Q000379:methods; D013816:Thermodynamics; D013997:Time Factors; D014867:Water / Q000737:chemistry*
chemical_list: D021301:Antifreeze Proteins; D002951:Citrates; D019476:Insect Proteins; D014867:Water; D000077559:Sodium Citrate