Annotated Bibliography
Barnes, Deborah E, Leland H Johnston, K-L Kodama, et al. 1990. Human DNA ligase I cDNA: cloning and functional expression in Saccharomyces cerevisiae. Proceedings of the National Academy of Sciences 87: 6679-6683.

CDNA clones encoding for DNA ligase I were isolated. In one method, human cDNA was screened using oligonucleotides from partial amino acid sequence of purified bovine DNA ligase I. and the second approach the human cDNA library was screened for functional expression of a polypeptide able to complement of a DNA ligase mutant of Saccharomyces cerevisiae. The sequence found encodes a 102 kDa protein indistinguishable from DNA ligase I. It was also found that the amino acid sequence of the human ligase I is 40% …show more content…
LIG1 and LIG4 encode a single DNA ligase polypeptide, while LIG3 gene encodes nuclear and mitochondrial versions of DNA ligase IIIα by alternative translation initiation and a germ cell-specific version, DNA ligase IIIβ, by alternative splicing. Steady-state fluorescence of AF488-labeled DNA oligonucleotides was measured in 1 cm × 1 cm quartz cuvettes. fluorescence emission was measured at 518 nm. thermal denaturation assays were performed using 20 nM DNA in 10 mM Tris–HCl [pH 8.0] to measure the thermodynamic stability of the folded DNA product. Measurement of parallel samples containing upstream AF488-labeled probe lacking the quencher moiety permitted the calculation of the quenching efficiency (EQ). the kinetic parameters of the DNA ligase have been determined, but they are not comparable because of the use of different DNA substrates and/or reaction conditions. In this experiment the activity of of purified recombinant hLigI, hLigIIIα/XRCC1, hLigIIIβ and hLigIV/XRCC4 have quantitated and compared the activities on DNA substrates that mimic DNA …show more content…
PCNA is a clamp which allows DNA polymerase to catalyze polymerization continuously without releasing the strand. Inactivation of this motif had no effect on catalytic activity or interaction with DNA polymerase β. However, inactivation seriously reduced the ability of ligase to join Okazaki fragments. This presents a major issue to the synthesis of the lagging-strand. A normal PCNA-binding site may really come into play for repairing DNA damage by alkylating agents. While short-patch base-excision repair [BER] was unaffected in Lig1 mutants, long-patch repair was