Adenylation domain of uncharacterized fungal ATP-dependent DNA ligase-like proteins
ATP-dependent polynucleotide ligases catalyze phosphodiester bond formation using nicked nucleic acid substrates with the high energy nucleotide of ATP as a cofactor in a three step reaction mechanism. DNA ligases play a vital role in the diverse processes of DNA replication, recombination and repair. ATP-dependent ligases are present in many organisms such as viruses, bacteriophages, eukarya, archaea and bacteria. This group is composed of uncharacterized fungal proteins with similarity to ATP-dependent DNA ligases. ATP dependent DNA ligases have a highly modular architecture consisting of a unique arrangement of two or more discrete domains including a DNA-binding domain, an adenylation (nucleotidyltransferase (NTase)) domain, and an oligonucleotide/oligosaccharide binding (OB)-fold domain. The adenylation domain binds ATP and contains many of the active-site residues. The adenylation and C-terminal OB-fold domains comprise a catalytic core unit that is common to most members of the ATP-dependent DNA ligase family. The catalytic core unit contains six conserved sequence motifs (I, III, IIIa, IV, V and VI) that define this family of related nucleotidyltransferases. This model characterizes the adenylation domain of this group of uncharacterized fungal proteins. It is not known whether these proteins also contain an OB-fold domain.
Comment:based on similarity to other members of the family
Comment:Sealing a nick in DNA requires three catalytic steps: first, enzyme adenylation is accomplished using ATP resulting in an AMP-linkage to the enzyme; second, the AMP is transferred to the 5' phosphate at the site of a nick; and third, phosphoryl transfer and sealing the nick DNA.
Jiyao W et al.(2023). "The conserved domain database in 2023.",