DNA ligases

DNA ligases

Enzymes that reconstitutes the double strand in a DNA molecule that has a discontinuity in one strand. DNA ligases join up the broken strand by catalyzing a PHOSPHODIESTER BOND at this point. From the Latin ligare , to bind.
References in periodicals archive ?
BER has 4 main steps (base removal, apurinic/apyrimidinic (AP) site incision, synthesis, and ligation) and involves 4 major classes of DNA repair enzymes: DNA glycosylases, apurinic/apyrimidinic endonucleases (APEs), DNA polymerases (DNA pols), and DNA ligases. Mammalian PARP-1 is a nuclear chromatin-associated multifunctional enzyme [56].
Chen, "Ischemic preconditioning induces XRCC1, DNA polymerase-beta, and DNA ligase III and correlates with enhanced base excision repair," DNA Repair, vol.
DNA ligases are enzymes that covalently join DNA strands by catalyzing the formation of a phosphodiester bond.
The EpiQassay exploited both the ability of DNA ligases to recognize DNA base mismatches at the ligation junction and the lowered melting temperatures of short mismatched DNA probes to achieve high assay specificity (Fig.
Restriction enzymes and T4 DNA ligases were purchased from New England Biolabs (Ipswich, MA).
Each ligation reaction (20 [micro]L) contained the restriction digestion product (10 [micro]L), 1 x T4 DNA ligase buffer with EDTA, 0.05 M NACl, 0.05 mg [mL.sup.-1] BSA, 6 U T4 DNA ligase, 10-pmol EcoRI adapter, 100-pmol MseI adapter and appropriate amount of water.
DNA ligases then join the DNA molecules with "sticky ends" to bacterial plasmids that also have been cleaved by restriction enzymes.
After trying T4 DNA ligases from different vendors, we decided to use highly concentrated enzyme (10 Weiss units/[micro]L) (23) provided by Epicentre.
For the annealing step, 500 pmol of appropriate 24mer and 20mer oligonucleotides were mixed in a 10-[micro]L volume of 1 x T4 DNA ligase buffer [33 mmol/L Tris-acetate (pH 7.8), 66 mmol/L potassium acetate, 10 mmol/L magnesium acetate, 0.5 mmol/L dithiothreitol], heated at 65[degrees]C for 5 min, and then allowed to cool slowly to room temperature.
Earlier studies had revealed that bacteriamutants with a defective DNA ligase also show characteristic chromosomal and DNA problems.
Results suggest it is the DNA ligase Ithat is defective.