Taq polymerase - wikipedia Taq polymerase Taq polymerase, exonuclease DNA polymerase bound to a DNA octamer Identifiers Symbol Taq - exonuc Pfam PF09281 InterPro IPR015361 SCOP 1qtm SUPERFAMILY 1qtm Available protein structures : Pfam structures PDB RCSB PDB ; PDBe ; PDBj PDBsum structure summary Taq - exonuc dna polymerase Identifiers Symbol Taq - exonuc Pfam PF09281 InterPro IPR015361 SCOP 1qtm SUPERFAMILY 1qtm Available protein structures : Pfam structures PDB RCSB PDB ; PDBe ; PDBj PDBsum structure summary Taq polymerase / ˌtæk ˈpɒlɪməreɪz / is a thermostable DNA polymerase named after the thermophilic bacterium Thermus aquaticus from which it was originally isolated by Chien et al. in 1976. Its name is often abbreviated to Taq Pol or simply Taq. It is frequently used in the polymerase chain reaction ( PCR ), a method for greatly amplifying the quantity of short segments of DNA. T. aquaticus is a bacterium that lives in hot springs and hydrothermal vents, and Taq polymerase was identified as an enzyme able to withstand the protein - denaturing conditions ( high temperature ) required during PCR. Therefore, it replaced the DNA polymerase from E. coli originally used in PCR. Taq 's optimum temperature for activity is 75 -- 80 ° C, with a half - life of greater than 2 hours at 92.5 ° C, 40 minutes at 95 ° C and 9 minutes at 97.5 ° C, and can replicate a 1000 base pair strand of DNA in less than 10 seconds at 72 ° C. One of Taq 's drawbacks is its lack of 3 ' to 5 ' exonuclease proofreading activity resulting in relatively low replication fidelity. Originally its error rate was measured at about 1 in 9,000 nucleotides. The remaining two domains act in coordination, via coupled domain motion. Some thermostable DNA polymerases have been isolated from other thermophilic bacteria and archaea, such as Pfu DNA polymerase, possessing a proofreading activity, and are being used instead of ( or in combination with ) Taq for high - fidelity amplification. Taq makes DNA products that have A ( adenine ) overhangs at their 3 ' ends. This may be useful in TA cloning, whereby a cloning vector ( such as a plasmid ) that has a T ( thymine ) 3 ' overhang is used, which complements with the A overhang of the PCR product, thus enabling ligation of the PCR product into the plasmid vector. Contents 1 In PCR 2 Patent issues 3 Protein domain 3.1 Function 3.2 Structure 4 See also 5 References In PCR In the early 1980s, Kary Mullis was working at Cetus Corporation on the application of synthetic DNAs to biotechnology. He was familiar with the use of DNA oligonucleotides as probes for binding to target DNA strands, as well as their use as primers for DNA sequencing and cDNA synthesis. In 1983, he began using two primers, one to hybridize to each strand of a target DNA, and adding DNA polymerase to the reaction. This led to exponential DNA replication, greatly amplifying the amounts of DNA between the primers. However, after each round of replication the mixture needs to be heated above 90 ° C to denature the newly formed DNA, allowing the strands to separate and act as templates in the next round of amplification. This heating step also inactivates the DNA polymerase that was in use before the discovery of Taq polymerase, the Klenow fragment of the DNA polymerase I from E. coli. Use of the thermostable Taq enables running the PCR at high temperature ( ~ 60 ° C and above ), which facilitates high specificity of the primers and reduces the production of nonspecific products, such as primer dimer. Also, use of a thermostable polymerase eliminates the need to add new enzyme to each round of thermocycling. A single closed tube in a relatively simple machine can be used to carry out the entire process. Thus, the use of Taq polymerase was the key idea that made PCR applicable to a large variety of molecular biology problems concerning DNA analysis. Patent issues Hoffmann - La Roche eventually bought the PCR and Taq patents from Cetus for $330 million, from which it may have received up to $2 billion in royalties. In 1989, Science Magazine named Taq polymerase its first `` Molecule of the Year ''. Kary Mullis received the Nobel Prize in 1993, the only one awarded for research performed at a biotechnology company. By the early 1990s, the PCR technique with Taq polymerase was being used in many areas, including basic molecular biology research, clinical testing, and forensics. It also began to find a pressing application in direct detection of the HIV in AIDS. In December 1999, U.S. District Judge Vaughn Walker ruled that the 1990 patent involving Taq polymerase was issued, in part, on misleading information and false claims by scientists with Cetus Corporation. The ruling supported a challenge by Promega Corporation against Hoffman - La Roche, which purchased the Taq patents in 1991. Judge Walker cited previous discoveries by other laboratories, including the laboratory of Professor John Trela in the University of Cincinnati department of biological sciences, as the basis for the ruling. Protein domain Function In molecular biology, this protein domain, Taq polymerase exonuclease, refers to a domain found in prokaryotic Taq DNA polymerase ( thermostable ). Structure This domain where it assumes a ribonuclease H - like motif. The domain confers 5 ' - 3 ' exonuclease activity to the polymerase. See also Wikimedia Commons has media related to Taq polymerase. Biological machines DNA polymerase I DNA replication Enzyme catalysis Protein domain dynamics References ^ Jump up to : Chien A, Edgar DB, Trela JM ( 1976 ). `` Deoxyribonucleic acid polymerase from the extreme thermophile Thermus aquaticus ''. J. Bact. 127 ( 3 ) : 1550 -- 7. PMC 232952. PMID 8432. ^ Jump up to : Saiki, RK ; et al. ( 1988 ). `` Primer - directed enzymatic amplification of DNA with a thermostable DNA polymerase. ''. Science. 239 ( 4839 ) : 487 -- 91. PMID 2448875. doi : 10.1126 / science. 2448875. ^ Jump up to : Saiki, RK ; et al. ( 1985 ). `` Enzymatic amplification of beta - globin genomic sequences and restriction site analysis for diagnosis of sickle cell anemia ''. Science. 230 ( 4732 ) : 1350 -- 4. PMID 2999980. doi : 10.1126 / science. 2999980. ^ Jump up to : Lawyer FC, et al. ( 1993 ). `` High - level expression, purification, and enzymatic characterization of full - length Thermus aquaticus DNA polymerase... ''. PCR Methods Appl. 2 ( 4 ) : 275 -- 87. PMID 8324500. doi : 10.1101 / gr. 2.4. 275. Jump up ^ Tindall KR, Kunkel TA ( 1988 ). `` Fidelity of DNA synthesis by the Thermus aquaticus DNA polymerase ''. Biochemistry. 27 ( 16 ) : 6008 -- 13. PMID 2847780. doi : 10.1021 / bi00416a027. Jump up ^ Bu Z, Biehl R, Monkenbusch M, Richter D, Callaway DJ ( December 2005 ). `` Coupled protein domain motion in Taq polymerase revealed by neutron spin - echo spectroscopy ''. Proc. Natl. Acad. Sci. U.S.A. 102 ( 49 ) : 17646 -- 51. PMC 1345721. PMID 16306270. doi : 10.1073 / pnas. 0503388102. Jump up ^ Mullis KB ( April 1990 ). `` The unusual origin of the polymerase chain reaction ''. Sci. Am. 262 ( 4 ) : 56 -- 61, 64 -- 5. PMID 2315679. doi : 10.1038 / scientificamerican0490 - 56. Jump up ^ Fore J, Wiechers IR, Cook - Deegan R ( 2006 ). `` The effects of business practices, licensing, and intellectual property on development and dissemination of the polymerase chain reaction : case study ''. J Biomed Discov Collab. 1 : 7. PMC 1523369. PMID 16817955. doi : 10.1186 / 1747 - 5333 - 1 - 7. Detailed history of Cetus Corporation and the commercial aspects of PCR. Jump up ^ Guatelli JC, Gingeras TR, Richman DD ( 1 April 1989 ). `` Nucleic acid amplification in vitro : detection of sequences with low copy numbers and application to diagnosis of human immunodeficiency virus type 1 infection ''. Clin. Microbiol. Rev. 2 ( 2 ) : 217 -- 26. PMC 358112. PMID 2650862. Jump up ^ Curran, Chris, Bio-Medicine, Dec. 7, 1999 Jump up ^ Li Y, Mitaxov V, Waksman G ( August 1999 ). `` Structure - based design of Taq DNA polymerases with improved properties of dideoxynucleotide incorporation ''. Proc. Natl. Acad. Sci. U.S.A. 96 ( 17 ) : 9491 -- 6. PMC 22236. PMID 10449720. doi : 10.1073 / pnas. 96.17. 9491. Transferases : phosphorus - containing groups ( EC 2.7 ) 2.7. 1 - 2.7. 4 : phosphotransferase / kinase ( PO ) 2.7. 1 : OH acceptor Hexo - Gluco - Fructo - Hepatic Galacto - Phosphofructo - Liver Muscle Platelet Riboflavin Shikimate Thymidine ADP - thymidine NAD Glycerol Pantothenate Mevalonate Pyruvate Deoxycytidine PFP Diacylglycerol Phosphoinositide 3 Class I PI 3 Class II PI 3 Sphingosine Glucose - 1, 6 - bisphosphate synthase 2.7. 2 : COOH acceptor Phosphoglycerate Aspartate kinase 2.7. 3 : N acceptor Creatine 2.7. 4 : PO acceptor Phosphomevalonate Adenylate Nucleoside - diphosphate Uridylate Guanylate Thiamine - diphosphate 2.7. 6 : diphosphotransferase ( P O ) Ribose - phosphate diphosphokinase Thiamine diphosphokinase 2.7. 7 : nucleotidyltransferase ( PO - nucleoside ) Polymerase DNA polymerase DNA - directed DNA polymerase II III IV V RNA - directed DNA polymerase Reverse transcriptase Telomerase DNA nucleotidylexotransferase / Terminal deoxynucleotidyl transferase RNA nucleotidyltransferase RNA polymerase / DNA - directed RNA polymerase RNA polymerase I RNA polymerase II RNA polymerase III RNA polymerase IV Primase RNA - dependent RNA polymerase PNPase Phosphorolytic 3 ' to 5 ' exoribonuclease RNase PH PNPase Nucleotidyltransferase UTP -- glucose - 1 - phosphate uridylyltransferase Galactose - 1 - phosphate uridylyltransferase Guanylyltransferase mRNA capping enzyme Other Recombinase ( Integrase ) Transposase 2.7. 8 : miscellaneous Phosphatidyltransferases CDP - diacylglycerol -- glycerol - 3 - phosphate 3 - phosphatidyltransferase CDP - diacylglycerol -- serine O - phosphatidyltransferase CDP - diacylglycerol -- inositol 3 - phosphatidyltransferase CDP - diacylglycerol -- choline O - phosphatidyltransferase Glycosyl - 1 - phosphotransferase N - acetylglucosamine - 1 - phosphate transferase 2.7. 10 - 2.7. 13 : protein kinase ( PO ; protein acceptor ) 2.7. 10 : protein - tyrosine see tyrosine kinases 2.7. 11 : protein - serine / threonine see serine / threonine - specific protein kinases 2.7. 12 : protein - dual - specificity see serine / threonine - specific protein kinases 2.7. 13 : protein - histidine Protein - histidine pros - kinase Protein - histidine tele - kinase Histidine kinase Enzymes Activity Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Regulation Allosteric regulation Cooperativity Enzyme inhibitor Classification EC number Enzyme superfamily Enzyme family List of enzymes Kinetics Enzyme kinetics Eadie -- Hofstee diagram Hanes -- Woolf plot Lineweaver -- Burk plot Michaelis -- Menten kinetics Types EC1 Oxidoreductases ( list ) EC2 Transferases ( list ) EC3 Hydrolases ( list ) EC4 Lyases ( list ) EC5 Isomerases ( list ) EC6 Ligases ( list ) Molecular and Cellular Biology portal Retrieved from `` https://en.wikipedia.org/w/index.php?title=Taq_polymerase&oldid=799410890 '' Categories : DNA replication EC 2.7. 7 Talk Contents About Wikipedia Bosanski Català Čeština Dansk Deutsch Español فارسی Français Galego 한국어 Italiano 日本 語 Norsk nynorsk Polski Português Русский Türkçe Українська 中文 Edit links This page was last edited on 7 September 2017, at 15 : 30. 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Question: what is the role of dna polymerase in pcr
Answer: DNA replication