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DNA ligase repairing chromosomal damage.
ligase I, DNA, ATP-dependent
Identifiers
Symbol	LIG1
Entrez	3978
HUGO	6598
OMIM	126391
RefSeq	NM_000234
UniProt	P18858
Other data
EC number	6.5.1.1
Locus	Chr. 19 [1]

In molecular biology, DNA ligase is a particular type of ligase (EC 6.5.1.1) that can link together two DNA strands that have single-strand breaks (a break in both complementary strands of DNA). The alternative, a double-strand break, is fixed by a different type of DNA ligase using the complementary strand as a template but still requires DNA ligase to create the final phosphodiester bond to fully repair the DNA. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... Look up Hugo in Wiktionary, the free dictionary. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... National Center for Biotechnology Information logo The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Short and long arms Chromosome. ... Chromosome 19 is one of the 23 pairs of chromosomes in humans. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... Look up Hugo in Wiktionary, the free dictionary. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... National Center for Biotechnology Information logo The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... Short and long arms Chromosome. ... Chromosome 17 is one of the 23 pairs of chromosomes in humans. ... The Entrez logo The Entrez Global Query Cross-Database Search System allows access to databases at the National Center for Biotechnology Information (NCBI) website. ... Look up Hugo in Wiktionary, the free dictionary. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... National Center for Biotechnology Information logo The National Center for Biotechnology Information (NCBI) is part of the United States National Library of Medicine (NLM), a branch of the National Institutes of Health. ... Swiss-Prot is a curated biological database of protein sequences created in 1986 by Amos Bairoch during his PhD and developed by the Swiss Institute of Bioinformatics and the European Bioinformatics Institute. ... Short and long arms Chromosome. ... Chromosome 13 is one of the 23 pairs of chromosomes in humans. ... Molecular biology is the study of biology at a molecular level. ... In biochemistry, a ligase (from the Latin verb ligāre — to bind or to glue together) is an enzyme that can catalyse the joining of two large molecules by forming a new chemical bond, usually with accompanying hydrolysis of a small chemical group pendant to one of the larger molecules. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... In genetics, complementary DNA (cDNA) is DNA synthesized from a mature mRNA template. ... Diagram of phosphodiester bonds between nucleotides A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a phosphate group and two other molecules over two ester bonds. ...

DNA ligase has applications in both DNA repair and DNA replication (see Mammalian ligases). In addition, DNA ligase has extensive use in molecular biology laboratories for Genetic recombination experiments (see Applications in molecular biology research). DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... DNA replication. ... In molecular biology, DNA ligase is a particular type of ligase (EC 6. ... Genetic recombination is the process by which a strand of the genetic material (usually DNA; but can also be RNA) is broken and then joined to the end of a different DNA molecule. ... In molecular biology, DNA ligase is a particular type of ligase (EC 6. ...

Ligase mechanism

The mechanism of DNA ligase is to form two covalent phosphodiester bonds between 3' hydroxyl ends of one nucleotide with the 5' phosphate end of another. ATP is not required for the ligase reaction. Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ... Diagram of phosphodiester bonds between nucleotides A phosphodiester bond is a group of strong covalent bonds between the phosphorus atom in a phosphate group and two other molecules over two ester bonds. ... In molecular biology, the 5 end and the 3 end (pronounced 5-prime and 3-prime) are respectively the leading and tail ends of a strand of nucleic acid. ... A nucleotide is a chemical compound that consists of 3 portions: a heterocyclic base, a sugar, and one or more phosphate groups. ... In molecular biology, the 5 end and the 3 end (pronounced 5-prime and 3-prime) are respectively the leading and tail ends of a strand of nucleic acid. ...

A pictorial example of how a ligase works (with sticky ends): This article or section does not cite its references or sources. ... Image File history File links Ligation. ...

Ligase will also work with blunt ends, although higher enzyme concentrations and different reaction conditions are required. This article or section does not cite its references or sources. ...

Mammalian ligases

In mammals, there are four specific types of ligase.

• DNA ligase I: ligates Okazaki fragments during lagging strand DNA replication and some recombinant fragments.
• DNA ligase II: alternatively spliced form of DNA ligase III found in non-dividing cells.
• DNA ligase III: complexes with DNA repair protein XRCC1 to aid in sealing base excision mutations and recombinant fragments.
• DNA ligase IV: complexes with XRCC4. It catalyzes the final step in the non-homologous end joining DNA double-strand break repair pathway. It is also required for V(D)J recombination, the process which generates diversity in immunoglobulin and T-cell receptor loci during immune system development.

An Okazaki fragment is a relatively short fragment of DNA created on the lagging strand during DNA replication. ... In DNA replication, the lagging strand is the DNA strand at the opposite side of the replication fork from the leading strand. ... DNA replication. ... Recombinant proteins are proteins that are produced by different genetically modified organisms following insertion of the relevant DNA into their genome. ... Splice has several meanings: In outdoor recreation (such as sailing or camping) rope splicing involves joining two pieces of rope or wire by weaving the strands of each into the other. ... A protein complex is a group of two or more associated proteins formed by protein-protein interaction that is stable over time. ... DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... RNA expression pattern Orthologs Human Mouse Entrez Ensembl Uniprot Refseq Location Pubmed search XRCC1 is a DNA repair protein. ... DNA damage resulting in multiple broken chromosomes DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecules that encode its genome. ... This article is about mutation in biology, for other meanings see: mutation (disambiguation). ... XRCC4 is a DNA repair protein. ... Non-homologous end joining (NHEJ) is one pathway that can be used to repair double-stranded DNA breaks. ... V(D)J recombination is a mechanism of DNA recombination used by humans and other vertebrates for immunological protection against attacks by bacterial, viral, and parasitic invaders. ... Schematic of antibody binding to an antigen An antibody is a protein complex used by the immune system to identify and neutralize foreign objects like bacteria and viruses. ... The T cell receptor or TCR is responsible for recognizing antigen bound to Major histocompatibility complex (MHC). ... A scanning electron microscope image of a single neutrophil (yellow), engulfing anthrax bacteria (orange). ...

Applications in molecular biology research

DNA ligases have become an indispensable tool in modern molecular biology research for generating recombinant DNA sequences. For example, DNA ligases are used with restriction enzymes to insert DNA fragments, often genes, into plasmids. Recombinant proteins are proteins that are produced by different genetically modified organisms following insertion of the relevant DNA into their genome. ... A restriction enzyme (or restriction endonuclease) is an enzyme that cuts double-stranded DNA. The enzyme makes two incisions, one through each of the sugar-phosphate backbones (i. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... Figure 1: Illustration of a bacterium with plasmids enclosed showing chromosomal DNA and plasmids. ...

One vital, and often tricky, aspect to performing successful recombination experiments involving ligase is controlling the optimal temperature. Most experiments use T4 DNA Ligase (isolated from bacteriophage T4) which is most active at 25°C. However in order to perform successful ligations, the optimal enzyme temperature needs to be balanced with the melting temperature T_m (also the annealing temperature) of the DNA fragments being ligated. Structural overview of the T4 phage Enterobacteria phage T4 is a phage that infects E. coli bacteria. ... The dissociation of a double-stranded DNA molecule is often referred to as melting because it occurs quickly once a certain temperature has been reached. ... Polymerase Chain Reaction (PCR) is a molecular biological technique for amplifying (creating multiple copies of) DNA without using a living organism, such as E. coli or yeast. ...

If the ambient temperature exceeds T_m, homologous pairing of the sticky ends will not occur because the high temperature disrupts hydrogen bonding. The shorter the DNA fragments, the lower the T_m. Thus for sticky ends (overlaps) less than ten base pairs long, ligation experiments are performed at very low temperatures (~4-8°C) for a long period of time (often overnight). Homologous chromosomes are chromosomes in a biological cell that pair (synapse) during meiosis, or alternatively, non-identical chromosomes that contain information for the same biological features and contain the same genes at the same loci but possibly different genetic information, called alleles, at those genes. ... In chemistry, a hydrogen bond is a type of attractive intermolecular force that exists between two partial electric charges of opposite polarity. ... In genetics, two nucleotides on opposite complementary DNA or RNA strands that are connected via hydrogen bonds are called a base pair (often abbreviated bp). ...

The common commercially available DNA ligases were originally discovered in bacteriophage T4, E. coli and other bacteria. Structural overview of the T4 phage Enterobacteria phage T4 is a phage that infects E. coli bacteria. ... See also Entamoeba coli. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ...

See also

• DNA end
• Lagging strand
• DNA replication
• Okazaki fragment
• DNA Polymerase

This article or section does not cite its references or sources. ... In DNA replication, the lagging strand is the DNA strand at the opposite side of the replication fork from the leading strand. ... DNA replication. ... This article does not cite any references or sources. ... 3D structure of the DNA-binding helix-hairpin-helix motifs in human DNA polymerase beta A DNA polymerase is an enzyme that assists in DNA replication. ...

External links

• DNA Ligase: PDB molecule of the month
• Davidson College General Information on Ligase
• OpenWetWare DNA Ligation Protocol