Stayton P S, Shimoboji T, Long C, Chilkoti A, Chen G, Harris J M, Hoffman A S
Center for Bioengineering, University of Washington, Seattle 98195, USA.
Nature. 1995 Nov 30;378(6556):472-4. doi: 10.1038/378472a0.
Stimuli-responsive polymers exhibit reversible phase changes in response to changes in environmental factors such as pH or temperature. Conjugating such polymers to antibodies and proteins provides molecular systems for applications such as affinity separations, immunoassays and enzyme recovery and recycling. Here we show that conjugating a temperature-sensitive polymer to a genetically engineered site on a protein allows the protein's ligand binding affinity to be controlled. We synthesized a mutant of the protein streptavidin to enable site-specific conjugation of the responsive polymer near the protein's binding site. Normal binding of biotin to the modified protein occurs below 32 degrees C, whereas above this temperature the polymer collapses and blocks binding. The collapse of the polymer and thus the enabling and disabling of binding, is reversible. Such environmentally triggered control of binding may find many applications in biotechnology and biomedicine, such as the control of enzyme reaction rates and of biosensor activity, and the controlled release of drugs.
刺激响应性聚合物会根据环境因素（如pH值或温度）的变化呈现可逆的相变。将此类聚合物与抗体和蛋白质结合，可为亲和分离、免疫测定以及酶的回收与循环利用等应用提供分子系统。在此我们表明，将温度敏感型聚合物与蛋白质上的基因工程位点结合，能够控制蛋白质的配体结合亲和力。我们合成了蛋白质抗生物素蛋白的一个突变体，以便在蛋白质结合位点附近实现响应性聚合物的位点特异性结合。生物素与修饰后的蛋白质在32摄氏度以下正常结合，而在此温度以上，聚合物会塌陷并阻止结合。聚合物的塌陷以及结合的开启与关闭是可逆的。这种由环境触发的结合控制在生物技术和生物医学领域可能有诸多应用，比如控制酶反应速率和生物传感器活性，以及控制药物的释放。
