Petka W A, Harden J L, McGrath K P, Wirtz D, Tirrell D A
Department of Polymer Science and Engineering, University of Massachusetts, Amherst, MA 01003, USA.
Science. 1998 Jul 17;281(5375):389-92. doi: 10.1126/science.281.5375.389.
Recombinant DNA methods were used to create artificial proteins that undergo reversible gelation in response to changes in pH or temperature. The proteins consist of terminal leucine zipper domains flanking a central, flexible, water-soluble polyelectrolyte segment. Formation of coiled-coil aggregates of the terminal domains in near-neutral aqueous solutions triggers formation of a three-dimensional polymer network, with the polyelectrolyte segment retaining solvent and preventing precipitation of the chain. Dissociation of the coiled-coil aggregates through elevation of pH or temperature causes dissolution of the gel and a return to the viscous behavior that is characteristic of polymer solutions. The mild conditions under which gel formation can be controlled (near-neutral pH and near-ambient temperature) suggest that these materials have potential in bioengineering applications requiring encapsulation or controlled release of molecular and cellular species.
重组DNA方法被用于创建人工蛋白质，这些蛋白质会根据pH值或温度的变化发生可逆凝胶化。这些蛋白质由位于中央柔性水溶性聚电解质片段两侧的末端亮氨酸拉链结构域组成。在近中性水溶液中，末端结构域形成卷曲螺旋聚集体会触发三维聚合物网络的形成，聚电解质片段保留溶剂并防止链沉淀。通过提高pH值或温度使卷曲螺旋聚集体解离会导致凝胶溶解，并恢复到聚合物溶液特有的粘性行为。凝胶形成可被控制的温和条件（近中性pH值和近环境温度）表明，这些材料在需要封装或控制分子和细胞种类释放的生物工程应用中具有潜力。
