DNA Ligase from T4-infected Escherichia coli is widely used in molecular biology for joining DNA fragments. It plays a crucial role in cloning experiments by sealing nicks in the DNA backbone, ensuring the integrity of recombinant DNA molecules. This enzyme is essential in the construction of plasmids, as it ligates insert DNA into vector DNA, enabling the replication of recombinant DNA in host cells. It is also utilized in DNA repair studies to understand and mimic natural DNA repair mechanisms. Additionally, T4 DNA Ligase is employed in next-generation sequencing (NGS) library preparation, where it ligates adapters to DNA fragments for sequencing. Its high efficiency and reliability make it a staple tool in genetic engineering, synthetic biology, and various biotechnological applications.