Antifreeze proteins (AFPs) or ice structuring proteins (ISPs) refer to a class of polypeptides produced by certain animals, plants, fungi and bacteria that permit their survival in temperatures below the freezing point of water. AFPs bind to small ice crystals to inhibit the growth and recrystallization of ice that would otherwise be fatal. Unlike the widely used automotive antifreeze, ethylene glycol, AFPs do not lower freezing point in proportion to concentration. Rather, they work in a noncolligative manner. This phenomenon allows them to act as an antifreeze at concentrations 1/300th to 1/500th of those of other dissolved solutes. Their low concentration minimizes their effect on osmotic pressure. AFPs create a difference between the melting point and freezing point (busting temperature of AFP bound ice crystal) known as thermal hysteresis. The addition of AFPs at the interface between solid ice and liquid water inhibits the thermodynamically favored growth of the ice crystal. Ice growth is kinetically inhibited by the AFPs covering the water-accessible surfaces of ice. Here you can see the structure of an antifreeze protein isolated from Typhula ishikariensis, an obligate fungal plant pathogen, determined by X-ray crystallography (PDB code: 7DDB)
#molecularart ... #immolecular ... #antifreeze ... #ice ... #crystallization ... #fungus ... #pathogen ... #plant ... #xray
Structure rendered with @proteinimaging and graphically composed with @corelphotopaint
#molecularart ... #immolecular ... #antifreeze ... #ice ... #crystallization ... #fungus ... #pathogen ... #plant ... #xray
Structure rendered with @proteinimaging and graphically composed with @corelphotopaint
