Bacteriophage T4 RNA ligase 1 (T4Rnl1)

Bacteriophage T4 RNA ligase 1 is a 43.5 kDa enzyme encoded by gene 63 of the T4 bacteriophage, which infects Escherichia coli. Its primary biological function is to catalyze the ATP-dependent covalent joining of single-stranded RNA or DNA ends through the formation of a 3'-5' phosphodiester bond. In its natural environment, the enzyme is involved in repairing host tRNA that has been cleaved by host defense mechanisms during phage infection. While the enzyme is not a therapeutic target for human disease, it is widely utilized in biotechnology as a fundamental molecular biology tool for RNA labeling, circularization, and the construction of cDNA libraries for next-generation sequencing. Its high efficiency in ligating single-stranded substrates makes it indispensable for synthetic biology and diagnostic assay development.

Other names

T4 RNA ligase 1gp63RNA ligase (ATP)Polyribonucleotide synthase (ATP)

The enzyme catalyzes the ATP-dependent ligation of a 5'-phosphoryl-terminated nucleic acid (donor) to a 3'-hydroxyl-terminated nucleic acid (acceptor) through a three-step mechanism: first, the enzyme is adenylated by ATP at a conserved lysine residue; second, the AMP is transferred to the 5'-phosphate of the donor to form an activated adenylated intermediate (AppN); third, the 3'-OH of the acceptor attacks the activated donor to form a phosphodiester bond and release AMP.