"表面互补"模型--抗冻蛋白通用的分子机理

抗冻蛋白(antifreeze protein,AFPs)是一类能控制冰晶生长和抑制冰晶之间发生重结晶的蛋白质,能在结冰或亚结冰条件下保护生物体不受伤害.AFPs具有两种明显不同的活性--热滞活性和重结晶抑制活性.AFPs虽然在氨基酸序列、物种来源和高级结构等方面具有很大的差异,但都能通过吸附作用与特定的冰晶表面相结合,从而表现出相应的抗冻活性.AFPs与冰晶结合的分子机理主要有"氢键结合"模型和"表面互补"模型,而后者具有更强的优势,已逐渐发展成AFPs通用性的分子机理.目前已测定或建模了三维结构的AFPs都能与冰晶的特定表面形成表面互补,但形成这种表面互补的各种作用力还有待于进一步的研究.

Model "Surface Complementarity" Points to a General Molecular Mechanism of Antifreeze Proteins

Antifreeze proteins (AFPs) are a family of proteins capable of protecting organisms from damage in freezing or sub_freezing conditions by controlling the growth of ice and inhibiting the recrystallization between ice granules, which were termed thermal hysteresis (TH) activity and recrystallization inhibition (RI) activity respectively. There is a distinct diversity between AFPs in amino acid sequence, species and higher_order structure, however, both AFPs exhibit suitable antifreeze activity by binding to a specific face of ice with adsorption. Two kinds of models of "hydrogen_bonding match" and "surface complementarity" were presented to explain the molecular mechanism of AFPs, and the latter has been gradually developed to the general mechanism for its stronger advantages. At present AFPs with solved or modeled three_dimensional structure can dock to specific faces of ice by surface complementarity, though diversified forces leading to the formation of this surface complementarity should be further investigated.