RECOGNITION AND CLEAVAGE BY RESTRICTION ENDONUCLEASES

了解蛋白质与dna的相互作用在基因水平上对对抗疾病至关重要。限制性内切酶对其识别序列具有高度特异性，是研究蛋白质- dna相互作用的良好模型系统。它们是限制性修饰系统的一部分，作为细菌细胞中抵抗噬菌体感染的原始免疫系统，通过高特异性切割噬菌体DNA，而宿主DNA则受到识别序列中特定甲基化的保护。此外，高特异性使得限制性内切酶在重组DNA技术中发挥重要作用。我建议结合生物物理方法研究FokI限制性内切酶的结构功能。FokI属于一种特殊的二部酶亚群，它在非回文识别序列外非特异性地切割DNA。马驹的两部分性质使其成为设计人工酶的极好候选者。这些研究将进一步了解识别和催化如何在限制性内切酶中偶联（或解偶联），并将有助于设计具有新特异性的限制性内切酶。

Understanding protein-DNA interaction is essential in the fight of diseases at the genetic level. Restriction endonucleases are excellent model systems to study protein-DNA interaction because of their high specificity towards their recognition sequence. They are part of restriction-modification systems and serve as a primitive immune system in bacterial cells against bacteriophage infection by cutting the phage DNA with high specificity, while the host DNA is protected by a specific methylation within the recognition sequence. Additionally, the high specificity gives restriction endonucleases an important role in recombinant DNA technologies. I propose to study the structure-function of the FokI restriction endonuclease using a combination of biophysical methods. FokI belongs to a special subgroup of bipartite enzymes that cleave DNA nonspecifically at a defined distance outside of a non- palindromic recognition sequence. The bipartite nature of FoAl makes it an excellent candidate for the design of artificial enzymes. The studies will provide further understanding how recognition and catalysis are coupled (or de-coupled) in restriction endonucleases and will aid the design of restriction enzymes with new specificities.