Cai J, Townsend J P, Dodson T C, Heiney P A, Sweeney A M
University of Pennsylvania, Department of Physics and Astronomy, Philadelphia, PA, USA.
University of Pennsylvania, Department of Biochemistry and Biophysics, Philadelphia, PA, USA.
Science. 2017 Aug 11;357(6351):564-569. doi: 10.1126/science.aal2674.
A parabolic relationship between lens radius and refractive index allows spherical lenses to avoid spherical aberration. We show that in squid, patchy colloidal physics resulted from an evolutionary radiation of globular S-crystallin proteins. Small-angle x-ray scattering experiments on lens tissue show colloidal gels of S-crystallins at all radial positions. Sparse lens materials form via low-valence linkages between disordered loops protruding from the protein surface. The loops are polydisperse and bind via a set of hydrogen bonds between disordered side chains. Peripheral lens regions with low particle valence form stable, volume-spanning gels at low density, whereas central regions with higher average valence gel at higher densities. The proteins demonstrate an evolved set of linkers for self-assembly of nanoparticles into volumetric materials.
晶状体半径与折射率之间的抛物线关系使球面透镜能够避免球面像差。我们发现，在鱿鱼中，球状S-晶体蛋白的进化辐射导致了斑驳的胶体物理学现象。对晶状体组织进行的小角X射线散射实验表明，在所有径向位置都存在S-晶体蛋白的胶体凝胶。稀疏的晶状体材料通过从蛋白质表面突出的无序环之间的低价键形成。这些环是多分散的，并通过无序侧链之间的一组氢键结合。粒子价低的周边晶状体区域在低密度下形成稳定的、跨越体积的凝胶，而平均价较高的中心区域在较高密度下形成凝胶。这些蛋白质展示了一组经过进化的连接子，用于将纳米颗粒自组装成体积材料。
