DNA ligase, shown above repairing chromosomal damage, is an enzyme that joins broken nucleotides together by catalyzing the formation of an internucleotide ester bond between the phosphate backbone and the deoxyribose nucleotides.
▶ DNA Replication: The Cell's Extreme Team Sport - YouTube. Ever wonder how all the new cells in your body get a copy of your DNA? DNA replication is a very intricate and fascinating process you don't want to miss. In this video, we'll give a brief overview of DNA replication for eukaryote cells and introduce 4 key players: ligase, DNA polymerase, primase, and helicase. We'll also talk about why DNA can either run 5' to 3' or 3' to 5' by exploring the structure of DNA.