DNA polymerases
| DNA-directed DNA polymerase | |||||||||
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3D structure of the DNA-binding helix-turn-helix motifs in human DNA polymerase beta (based on PDB file 7ICG)
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| Identifiers | |||||||||
| EC number | 2.7.7.7 | ||||||||
| CAS number | 9012-90-2 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDB PDBe PDBsum | ||||||||
| Gene Ontology | AmiGO / EGO | ||||||||
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| Search | |
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| PMC | articles |
| PubMed | articles |
| NCBI | proteins |
| DNA polymerase family A | |||||||||
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c:o6-methyl-guanine pair in the polymerase-2 basepair position
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| Identifiers | |||||||||
| Symbol | DNA_pol_A | ||||||||
| Pfam | PF00476 | ||||||||
| InterPro | IPR001098 | ||||||||
| SMART | - | ||||||||
| PROSITE | PDOC00412 | ||||||||
| SCOP | 1dpi | ||||||||
| SUPERFAMILY | 1dpi | ||||||||
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| Available protein structures: | |
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| Pfam | structures |
| PDB | RCSB PDB; PDBe; PDBj |
| PDBsum | structure summary |
| DNA polymerase family B | |||||||||
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crystal structure of rb69 gp43 in complex with dna containing thymine glycol
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| Identifiers | |||||||||
| Symbol | DNA_pol_B | ||||||||
| Pfam | PF00136 | ||||||||
| Pfam clan | CL0194 | ||||||||
| InterPro | IPR006134 | ||||||||
| PROSITE | PDOC00107 | ||||||||
| SCOP | 1noy | ||||||||
| SUPERFAMILY | 1noy | ||||||||
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| Available protein structures: | |
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| Pfam | structures |
| PDB | RCSB PDB; PDBe; PDBj |
| PDBsum | structure summary |
| DNA polymerase type B, organellar and viral | |||||||||
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phi29 dna polymerase, orthorhombic crystal form, ssdna complex
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| Identifiers | |||||||||
| Symbol | DNA_pol_B_2 | ||||||||
| Pfam | PF03175 | ||||||||
| Pfam clan | CL0194 | ||||||||
| InterPro | IPR004868 | ||||||||
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| Available protein structures: | |
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| Pfam | structures |
| PDB | RCSB PDB; PDBe; PDBj |
| PDBsum | structure summary |
In molecular biology, DNA polymerases are enzymes that synthesize DNA molecules from deoxyribonucleotides, the building blocks of DNA. These enzymes are essential to DNA replication and usually work in pairs to create two identical DNA strands from a single original DNA molecule. During this process, DNA polymerase "reads" the existing DNA strands to create two new strands that match the existing ones.
These enzymes catalyze the following chemical reaction
Catalyses DNA-template-directed extension of the 3'- end of a DNA strand by one nucleotide at a time.
Every time a cell divides, DNA polymerases are required to help duplicate the cell's DNA, so that a copy of the original DNA molecule can be passed to each daughter cell. In this way, genetic information is passed down from generation to generation.
Before replication can take place, an enzyme called helicase unwinds the DNA molecule from its tightly woven form. This opens up or "unzips" the double-stranded DNA to give two single strands of DNA that can be used as templates for replication.
In 1956, Arthur Kornberg and colleagues discovered DNA polymerase I (Pol I), in Escherichia coli. They described the DNA replication process by which DNA polymerase copies the base sequence of a template DNA strand. Kornberg was later awarded the Nobel Prize in Physiology or Medicine in 1959 for this work.DNA polymerase II was also discovered by Thomas Kornberg (the son of Arthur Kornberg) and Malcolm E. Gefter in 1970 while further elucidating the role of Pol I in E. coli DNA replication.
The main function of DNA polymerase is to synthesize DNA from deoxyribonucleotides, the building blocks of DNA. The DNA copies are created by the pairing of nucleotides to bases present on each strand of the original DNA molecule. This pairing always occurs in specific combinations, with cytosine along with guanine, and thymine along with adenine, forming two separate pairs, respectively. By contrast, RNA polymerases synthesize RNA from ribonucleotides from either RNA or DNA.
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Wikipedia