AP BIOLOGY

Detailed explanation-1: -DNA ligases play an essential role in maintaining genomic integrity by joining breaks in the phosphodiester backbone of DNA that occur during replication and recombination, and as a consequence of DNA damage and its repair.

Detailed explanation-2: -DNA ligase fills the spaces between the different fragments to bridge together the gaps in DNA. It accomplishes this by creating phosphodiester bonds between the 3’ end of one nucleotide and the 5’ end of the next nucleotide.

Detailed explanation-3: -DNA ligases seal 5′-PO4 and 3′-OH polynucleotide ends via three nucleotidyl transfer steps involving ligase-adenylate and DNA-adenylate intermediates.

Detailed explanation-4: -Abstract. T4 DNA ligase is an Mg2+-dependent and ATP-dependent enzyme that seals DNA nicks in three steps: it covalently binds AMP, transadenylates the nick phosphate, and catalyses formation of the phosphodiester bond releasing AMP.

Detailed explanation-5: -Joining two or more DNA fragments via a ligase-catalyzed reaction (a ligation) is a fundamental technique in recombinant DNA technology and genetic engineering. The ligation of different DNA fragments can create new functional units. Many organisms can be genetically modified via recombinant DNA technology.