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TREX2
Three prime repair exonuclease 2 is an enzyme that in humans is encoded by the ''TREX2'' gene. This gene encodes a protein with 3' exonuclease activity. Enzymes with this activity are involved in DNA replication, repair, and recombination. Similarity to an E. coli protein suggests that this enzyme may be a subunit of DNA polymerase III DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of ..., which does not have intrinsic exonuclease activity. Mutations in this gene may lead to Aicardi-Goutieres syndrome References Further reading * * * * * * * * * * * * * * * * * * * External links * * {{protein-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exonuclease III
Exonuclease III (ExoIII) is an enzyme that belongs to the exonuclease family. ExoIII catalyzes the stepwise removal of mononucleotides from 3´-hydroxyl termini of double-stranded DNA. A limited number of nucleotides are removed during each binding event, resulting in coordinated progressive deletions within the population of DNA molecules. Function The preferred substrates are blunt or recessed 3´-termini, although ExoIII also acts at nicks in duplex DNA to produce single-strand gaps. The enzyme is not active on single-stranded DNA, and thus 3´-protruding termini are resistant to cleavage. The degree of resistance depends on the length of the extension, with extensions 4 bases or longer being essentially resistant to cleavage. This property is used to produce unidirectional deletions from a linear molecule with one resistant (3´-overhang) and one susceptible (blunt or 5´-overhang) terminus. ExoIII activity depends partially on the DNA helical structure and displays sequen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Replication
In molecular biology, DNA replication is the biological process of producing two identical replicas of DNA from one original DNA molecule. DNA replication occurs in all living organisms acting as the most essential part for biological inheritance. This is essential for cell division during growth and repair of damaged tissues, while it also ensures that each of the new cells receives its own copy of the DNA. The cell possesses the distinctive property of division, which makes replication of DNA essential. DNA is made up of a double helix of two complementary strands. The double helix describes the appearance of a double-stranded DNA which is thus composed of two linear strands that run opposite to each other and twist together to form. During replication, these strands are separated. Each strand of the original DNA molecule then serves as a template for the production of its counterpart, a process referred to as semiconservative replication. As a result of semi-conservative rep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Polymerase III Holoenzyme
DNA polymerase III holoenzyme is the primary enzyme complex involved in prokaryotic DNA replication. It was discovered by Thomas Kornberg (son of Arthur Kornberg) and Malcolm Gefter in 1970. The complex has high processivity (i.e. the number of nucleotides added per binding event) and, specifically referring to the replication of the '' E.coli'' genome, works in conjunction with four other DNA polymerases (Pol I, Pol II, Pol IV, and Pol V). Being the primary holoenzyme involved in replication activity, the DNA Pol III holoenzyme also has proofreading capabilities that corrects replication mistakes by means of exonuclease activity reading 3'→5' and synthesizing 5'→3'. DNA Pol III is a component of the replisome, which is located at the replication fork. Components The replisome is composed of the following: *2 DNA Pol III enzymes, each comprising α, ε and θ subunits. (It has been proven that there is a third copy of Pol III at the replisome.) **the α subunit (encode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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