Broomell Christopher C, Khan Rashda K, Moses Dana N, Miserez Ali, Pontin Michael G, Stucky Galen D, Zok Frank W, Waite J Herbert
Department of Molecular Cell & Developmental Biology, University of California, Santa Barbara, CA 93106, USA.
J R Soc Interface. 2007 Feb 22;4(12):19-31. doi: 10.1098/rsif.2006.0153.
Contrary to conventional wisdom, mineralization is not the only strategy evolved for the formation of hard, stiff materials. Indeed, the sclerotized mouthparts of marine invertebrates exhibit Young's modulus and hardness approaching 10 and 1 GPa, respectively, with little to no help from mineralization. Based on biochemical analyses, three of these mouthparts, the jaws of glycerid and nereid polychaetes and a squid beak, reveal a largely organic composition dominated by glycine- and histidine-rich proteins. Despite the well-known metal ion binding by the imidazole side-chain of histidine and the suggestion that this interaction provides mechanical support in nereid jaws, there is at present no universal molecular explanation for the relationship of histidine to mechanical properties in these sclerotized structures.
与传统观念相反，矿化并不是形成坚硬、刚性材料的唯一进化策略。事实上，海洋无脊椎动物的硬化口器的杨氏模量和硬度分别接近10 GPa和1 GPa，几乎没有矿化作用的帮助。基于生化分析，这些口器中的三种，即甘油虫和沙蚕多毛类动物的颚以及鱿鱼喙，显示出主要由富含甘氨酸和组氨酸的蛋白质组成的有机成分。尽管众所周知组氨酸的咪唑侧链能结合金属离子，并且有人认为这种相互作用为沙蚕颚提供了机械支撑，但目前对于这些硬化结构中组氨酸与机械性能之间的关系尚无普遍的分子解释。
