Molecular mechanism of aragonite crystal formation by proteins from Pteria penguin pearl shell, and its application to the development of functional materials

从企鹅珍珠贝（Pteria penguin pearl shell）的壳中分离得到了新的26 kDa ADP核糖基转移酶样蛋白（ARTL 26 Ps）和Jacalin相关凝集素（JRL）。为了探讨ARTL 26 Ps在生物矿化中的分子机制，我们利用荧光标记的ARTL 26 P-1和ARTL 26 P-2进行体外晶体生长实验，结果发现这两种蛋白质的一级序列除了4个氨基酸外完全相同，但在体外却表现出不同的分布和功能。ARTL 26 P-2促进CaCO_3成核，增加晶体数量，ARTL 26 P-1调节CaCO_3晶体形貌。因此，ART样26 kDa蛋白通过企鹅珍珠层贝壳中文石晶体的成核和生长来调节文石晶体的形成。另一方面，JRL显示序列相似性，有趣的是它们具有相当不同的碳水化合物结合特异性。体外CaCO 3结晶实验表明，PPL 2A对企鹅珍珠贝的生物矿化有促进作用，并使其结晶量增加，而PPL 3则抑制其结晶。

Novel 26 kDa ADP rybosyl transferase-like proteins (ARTL26Ps)and Jacalin-related lectins (JRLs)were isolated from the muntle of Pteria penguin pearl shell. To investigate the molecular mechanisms of ARTL26Ps in biomineralization, we achieved in vitro crystal growth experiments using fluorescent-labeled ARTL26P-1 and-2, resulting these two proteins showed the different distribution and functions although their primary sequences were identical except for only 4 amino acids. ARTL26P-2 promoted the nucleation and increased the number of crystals, while ARTL26P-1 regulated the molphologies of CaCO_3 crystals. Thus the ART-like 26 kDa proteins regulate the aragonite crystal formation via nucleation and growth of aragonite crystals in P. penguin nacre shell. On the other hand, JRLs showed the sequence similarities, interestingly they had quite different carbohydrate binding specificities. Furthermore, CaCO3 crystalization in vitro indicated that PPL2A affected on the biomineralization of Pteria penguin with increasing crystals, while PPL3 inhibited the crystalization.