Polynucleotide ligase

DNA ligase (NAD+) [EC 6.5.1.2] (also referred to as polydeoxyribonucleotide synthase (NAD+), polynucleotide ligase (NAD+), DNA repair enzyme, and DNA join-ase) catalyzes the reaction of NAD+ with (deoxyribo-nucleotide) and (deoxyribonucleotide) to produce AMP, nicotinamide nucleotide, and (deoxyribonucleo-tide)( +m). This forms a phosphodiester at the site of a single-strand break in duplex DNA. RNA can also act as substrate to some extent. 

As mentioned earlier, discontinuous DNA synthesis necessitates the existence of an enzyme for joining the newly synthesized segments (see fig. 26.6). Such an enzyme has been found in a variety of cell types and is called polynucleotide ligase (fig. 26.9). 

Shuman S, Lima CD (2004) The polynucleotide ligase and RNA capping enzyme superfamily of covalent nucleotidyltransferases. Curr Opin Struct Biol 14 757-764. doi 10.1016/ j.sbi.2004.10.006... 

S. Shuman, Y. Liu, and B. Schwer. 1994. Covalent catalysis in nucleotidyl transfer reactions Essential motifs in Saccharomyces cerevisiae RNA capping enzyme are conserved in Schizosaccharomyces pombe and viral capping enzymes and among polynucleotide ligases Proc. Natl. Acad. Sci. U. S. A. 91 12046-12050. (PubMed) (Full Text in PMC)... 

Finally, the Okazaki fragments are joined by polynucleotide ligase, an enzyme that catalyzes formation of phos-phodiester bonds between two polynucleotide chains. 

D. Polynucleotide ligase joins DNA chains together. Polymerases can only add one nucleotide at a time to the 3 end of a growing chain. An endonuclease cleaves DNA strands. 

An enzyme-adenylate intermediate in the polynucleotide ligase reaction. / Biol. Chem. 243 4556-4563. See also Lehman, l.R. (1974). DNA ligase Structure, mechanism, and function. Science 186 790-797, for a complete review.)... 

Lindahl, T., and G. M. Edelman. 1968. Polynucleotide ligase from myeloid and lymphoid tissues. Proc. Nat. Acad. Sci. U.SA., 61 680-687. 

Teraoka H, Shomoyachi M, Tsukada K (1975) Two distinct polynucleotide ligases from rat liver. FEBS Lett 54 217-220... 

Beaid F (1972) Polynucleotide ligase in mouse cells infected by polyoma virus. Biochim Biophys Acta 269 385-396... 

Bertazzoni U, Mathelet M, Campagnari F (1972) Purification and properties of a polynucleotide ligase from calf thymus glands. Biochim Biophys Acta 287 404-414... 

Sambrook, j., Shatkin, A. J. Polynucleotide ligase activity in cells infected with simian virus 40, polyoma virus, or vaccinia virus. J. Virol. 4, 719-726 (1969). 

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