Local ice melting by an antifreeze protein.
Antifreeze proteins, AFP, impede freezing of bodily fluids and damaging of cellular tissues by low temperatures. Adsorption-inhibition mechanisms have been developed to explain their functioning. Using in silico Molecular Dynamics, we show that type I AFP can also induce melting of the local ice surface. Simulations of antifreeze-positive and antifreeze-negative mutants show a clear correlation between melting induction and antifreeze activity. The presence of local melting adds a function to type I AFPs that is unique to these proteins. It may also explain some apparently conflicting experimental results where binding to ice appears both quasipermanent and reversible.
Dipartimento di Chimica G. Ciamician, Università di Bologna, Bologna, Italy. matteo.calvaresi@studio.unibo.it
Matteo
M
Calvaresi
Siegfried
S
Höfinger
Francesco
F
Zerbetto
D019943:Amino Acid Substitution; D021322:Antifreeze Proteins, Type I / Q000737:chemistry*; D029941:Fish Proteins / Q000737:chemistry*; D005615:Freezing; D006860:Hydrogen Bonding; D056004:Molecular Dynamics Simulation; D025341:Principal Component Analysis; D017433:Protein Structure, Secondary; D044366:Transition Temperature; D014867:Water / Q000737:chemistry*
D021322:Antifreeze Proteins, Type I; D029941:Fish Proteins; D014867:Water