Miura K, Ohgiya S, Hoshino T, Nemoto N, Suetake T, Miura A, Spyracopoulos L, Kondo H, Tsuda S
Bioscience and Chemistry Division, Hokkaido National Industrial Research Institute, 2-17-2-1 Tsukisamu-Higashi, Toyohira, Sapporo 062-8517, Japan.
J Biol Chem. 2001 Jan 12;276(2):1304-10. doi: 10.1074/jbc.M007902200.
The structure of a new antifreeze protein (AFP) variant, RD3, from antarctic eel pout (Rhigophila dearborni) with enhanced activity has been determined for the first time by nuclear magnetic resonance spectroscopy. RD3 comprises a unique translational topology of two homologous type III AFP globular domains, each containing one flat, ice binding plane. The ice binding plane of the N domain is located approximately 3.5 A "behind" that of the C domain. The two ice binding planes are located laterally with an angle of 32 +/- 12 degrees between the planes. These results suggest that the C domain plane of RD3 binds first to the ice [1010] prism plane in the <0001> direction, which induces successive ice binding of the N domain in the <0101> direction. This manner of ice binding caused by the unique structural topology of RD3 is thought to be crucial for the significant enhancement of antifreeze activity, especially at low AFP concentrations.
通过核磁共振光谱首次确定了来自南极鳗鲡（Rhigophila dearborni）的具有增强活性的新型抗冻蛋白（AFP）变体RD3的结构。RD3由两个同源III型AFP球状结构域组成独特的翻译拓扑结构，每个结构域都包含一个平坦的冰结合平面。N结构域的冰结合平面位于C结构域的冰结合平面“后方”约3.5埃处。两个冰结合平面横向定位，平面之间的角度为32±12度。这些结果表明，RD3的C结构域平面首先在<0001>方向上与冰[1010]棱柱平面结合，这会诱导N结构域在<0101>方向上连续与冰结合。由RD3独特的结构拓扑引起的这种冰结合方式被认为对于显著增强抗冻活性至关重要，尤其是在低AFP浓度下。
