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What is DNA polymerase III?
Dna Pol three is a Dna copying bio-machine - similar more in function than in overall shapes and forms {and cofactors} to Dna Pol I and Dna Pol II - each has It's own special Role [ regarding Dna replication ( synthesis of two new Dna intertwined strands ) ] to perform.
What is the difference between DNA polymerase I II and III?
DNA polymerase I, II, and III are enzymes involved in DNA replication in prokaryotes. DNA polymerase I is responsible for removing RNA primers during DNA replication and filling the gaps with DNA nucleotides. DNA polymerase II is involved in DNA repair pathways, particularly in response to DNA damage. DNA polymerase III is the main enzyme responsible for synthesizing a new DNA strand during replication. It has a high processivity and is the primary enzyme involved in synthesizing the leading and lagging strands of DNA.
What are the 2 enzymes involved in duplicating DNA?
More than two enzymes are involved, but the main ones are DNA Polymerases (Pol III and Pol I in Prokaryotes, Pol α, Pol δ and Pol ε in Eukaryotes).In vitro you can achieve replication with only taq polymerase and two primers.
What enzyme attaches and adds the matching nucleotides?
DNA Polymerase III adds nucleotides during DNA replication. DNA Polymerase I also adds nucleotides (to a lesser extent). DNA Pol I is responsible for replacing the primers with dNTPs, these sections are then joined to the rest by DNA Ligase.
How many types of DNA polymerase are there?
There are 5 known Prokaryotic DNA polymerases:Pol I: implicated in DNA repair; has 5'->3' polymerase activity, and both 3'->5' exonuclease activity (proofreading) and 5'->3' exonuclease activity (RNA primer removal).Pol II: involved in repairing damaged DNA; has 3'->5' exonuclease activity.Pol III: the main polymerase in bacteria (responsible for elongation); has 3'->5' exonuclease activity (proofreading).Pol IV: a Y-family DNA polymerase.Pol V: a Y-family DNA polymerase; participates in bypassing DNA damage.There are at least 15 Eukaryotic DNA polymerase:POLA1, POLA2: Pol α (also called RNA primase): forms a complex with a small catalytic (PriS) and a large noncatalytic (PriL) subunit, with the Pri subunits acting as a primase (synthesizing an RNA primer), and then with DNA Pol α elongating that primer with DNA nucleotides. After around 20 nucleotides elongation is taken over by Pol ε (on the leading strand) and δ (on the lagging strand).POLB: Pol β: Implicated in repairing DNA, in base excision repair and gap-filling synthesis.POLG, POLG2: Pol γ: Replicates and repairs mitochondrial DNA and has proofreading 3'->5' exonuclease activity.POLD1, POLD2, POLD3, POLD4: Pol δ: Highly processive and has proofreading 3'->5' exonuclease activity. Thought to be the main polymerase involved in lagging strand synthesis, though there is still debate about its role.POLE, POLE2, POLE3: Pol ε: Also highly processive and has proofreading 3'->5' exonuclease activity. Highly related to pol δ, and thought to be the main polymerase involved in leading strand synthesis, though there is again still debate about its role.POLH, POLI, POLK, : η, ι, κ, and Rev1 are Y-family DNA polymerases and Pol ζ is a B-family DNA polymerase. These polymerases are involved in the bypass of DNA damage.There are also other eukaryotic polymerases known, which are not as well characterized: POLQ: 'θPOLL: λ?: φ?: σPOLM: μDNA polymerase familiesBased on sequence homology, DNA polymerases can be further subdivided into seven different families: A, B, C, D, X, Y, and RT. Family_A">Family APolymerases contain both replicative and repair polymerases. Replicative members from this family include the extensively-studied T7 DNA polymerase, as well as the eukaryotic mitochondrial DNA Polymerase γ. Among the repair polymerases are Escherichia coli DNA pol I, Thermus aquaticus pol I, and Bacillus stearothermophilus pol I. These repair polymerases are involved in excision repair and processing of Okazaki fragments generated during lagging strand synthesis. Family BPolymerases mostly contain replicative polymerases and include the major eukaryotic DNA polymerases α, δ, ε, (see Greek letters) and also DNA polymerase ζ. Family B also includes DNA polymerases encoded by some bacteria and bacteriophages, of which the best-characterized are from T4, Phi29, and RB69 bacteriophages. These enzymes are involved in both leading and lagging strand synthesis during replication. A hallmark of the B family of polymerases is their highly faithful DNA synthesis during replication. While many have an intrinsic 3'-5' proofreading exonuclease activity, eukaryotic DNA polymerases α and ζ are two examples of B family polymerases lacking this proofreading activity.Family_C">Family CPolymerases are the primary bacterial chromosomal replicative enzymes. DNA Polymerase III alpha subunit from E. coli is the catalytic subunit [1] and possesses no known nuclease activity. A separate subunit, the epsilon subunit, possesses the 3'-5' exonuclease activity used for editing during chromosomal replication. Recent research has classified Family C polymerases as a subcategory of Family X[citation needed]. Family_D">Family DPolymerases are still not very well characterized. All known examples are found in the Euryarchaeota subdomain of Archaea and are thought to be replicative polymerases. Family_X">Family XContains the well-known eukaryotic polymerase pol β, as well as other eukaryotic polymerases such as pol σ, pol λ, pol μ, and terminal deoxynucleotidyl transferase (TdT). Pol β is required for short-patch base excision repair, a DNA repair pathway that is essential for repairing abasic sites. Pol λ and Pol μ are involved in non-homologous end-joining, a mechanism for rejoining DNA double-strand breaks. TdT is expressed only in lymphoid tissue, and adds "n nucleotides" to double-strand breaks formed during V(D)J recombination to promote immunological diversity. The yeast Saccharomyces cerevisiae has only one Pol X polymerase, Pol IV, which is involved in non-homologous end-joining. Family_Y">Family YY Polymerases differ from others in having a low fidelity on undamaged templates and in their ability to replicate through damaged DNA. Members of this family are hence called translesion synthesis (TLS) polymerases. Depending on the lesion, TLS polymerases can bypass the damage in an error-free or error-prone fashion, the latter resulting in elevated mutagenesis. Xeroderma pigmentosum variant (XPV) patients for instance have mutations in the gene encoding Pol η (eta), which is error-free for UV-lesions. In XPV patients, alternative error-prone polymerases, e.g., Pol ζ (zeta) (polymerase ζ is a B Family polymerase a complex of the catalytic subunit REV3L with Rev7, which associates with Rev1[2]), are thought to be involved in mistakes that result in the cancer predisposition of these patients. Other members in humans are Pol ι (iota), Pol κ (kappa), and Rev1 (terminal deoxycytidyl transferase). In E. coli, two TLS polymerases, Pol IV (DINB) and Pol V (UmuD'2C), are known. Family RTThe reverse transcriptase family contains examples from both retroviruses and eukaryotic polymerases. The eukaryotic polymerases are usually restricted to telomerases. These polymerases use an RNA template to synthesize the DNA strand.Variety across Species:DNA polymerases have highly-conserved structure, which means that their overall catalytic subunits vary, on a whole, very little from species to species. Conserved structures usually indicate important, irreplaceable functions of the cell, the maintenance of which provides evolutionary advantages. Some viruses also encode special DNA polymerases, such as Hepatitis B virus DNA polymerase. These may selectively replicate viral DNA through a variety of mechanisms. Retroviruses encode an unusual DNA polymerase called reverse transcriptase, which is an RNA-dependent DNA polymerase (RdDp). It polymerizes DNA from a template of RNA.
What is the difference between DNA polymerase III and DNA polymerase I?
pol 1 - exonuclease activity pol 2 - dna repair pol 3 - primary replication enzyme
What is the enzyme responsible for attaching free floating nucleotides to an open strand of DNA for replication?
Polymerase - in prokaryotes this is accomplished by pol III at the DNA fork. In eukaryotes this is performed by pol delta.
What is DNA polymerase III?
Dna Pol three is a Dna copying bio-machine - similar more in function than in overall shapes and forms {and cofactors} to Dna Pol I and Dna Pol II - each has It's own special Role [ regarding Dna replication ( synthesis of two new Dna intertwined strands ) ] to perform.
What is the difference between DNA polymerase I II and III?
DNA polymerase I, II, and III are enzymes involved in DNA replication in prokaryotes. DNA polymerase I is responsible for removing RNA primers during DNA replication and filling the gaps with DNA nucleotides. DNA polymerase II is involved in DNA repair pathways, particularly in response to DNA damage. DNA polymerase III is the main enzyme responsible for synthesizing a new DNA strand during replication. It has a high processivity and is the primary enzyme involved in synthesizing the leading and lagging strands of DNA.
What is the function of DNA polymerase?
DNA polymerases are the enzymes responsible for joining DNA nucleotides together. In Prokaryotes - DNA Pol III is the enzyme which adds nucleotides to the new strand during DNA replication. DNA Pol I is responsible for replacing the primers with DNA nucleotides.
Why DNA pol needs 3'OH to attach new nucleotide?
possibly,for the structure of DNA pol..........
What are the 2 enzymes involved in duplicating DNA?
More than two enzymes are involved, but the main ones are DNA Polymerases (Pol III and Pol I in Prokaryotes, Pol α, Pol δ and Pol ε in Eukaryotes).In vitro you can achieve replication with only taq polymerase and two primers.
Which enzyme is the key player in replication?
In prokaryotes: DNA gyrase - a topoisomerase II protein that introduces negative supercoils in the DNA to reduce torsional stressDNA helicase - breaks the hydrogen bonds between nucleotides and unzips the DNA double helixSingle stranded binding proteins - stabilize DNA be keeping the DNA strands from reannealingDNA Polymerase III - polymerizes nucleotides forming a new DNA strandLoading clamp - loads the DNA strand into pol IIIDNA Primase - lays down an RNA primer on the lagging strandDNA Polymerase I - replaces RNA primer with DNADNA Ligase - ligates DNA strand together on the lagging strandIn eukaryotes:DNA Pol III is replaced by DNA Pol DeltaPol I is replaced by Pol AlphaRPA - replication protein A replaces the SSBsRFC - replication factor C replaces DNA loading clampPCNA replaces the beta subunit
What enzyme attaches and adds the matching nucleotides?
DNA Polymerase III adds nucleotides during DNA replication. DNA Polymerase I also adds nucleotides (to a lesser extent). DNA Pol I is responsible for replacing the primers with dNTPs, these sections are then joined to the rest by DNA Ligase.
What happens if DNA pol 1 is nonfunctional in the replicated genome?
Nothing gets added on to the DNA. Pol I is suppose to repair damaged sequences , so if it is nonfunctional, the damage sequences remain causing a mutated gene sequence.
What enzyme elongates DNA?
DNA Polymerase III
What are the four enzymes involved in DNA replication and repair?
DNA polymerase III DNA polymerase I DNA Ligase DNA Helicase
