DNA polymerase: Difference between revisions
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===Family A=== | ===Family A=== | ||
In addition to the basic structure of DNA polymerase, the Family A polymerases also | In addition to the basic structure of DNA polymerase, the Family A polymerases also has a 5'-3' exonuclease that is required for the removal of RNA primers from Okazaki fragments. Not all, but some Family A polymerases also a 3'-5' exonuclease that is responsible for proofreading the DNA. <ref>PMID: 16230118</ref> | ||
===Family B=== | ===Family B=== | ||
In addition to the basic structure of DNA polymerase, the Family B polymerases contain | In addition to the basic structure of DNA polymerase, the Family B polymerases contain an extremely active 3'-5' exonuclease that corrects errors in DNA replication. | ||
===Family X=== | ===Family X=== | ||
The thumb, palm, and fingers subdomains are a part of the of N-terminal, or 31-kDA polymerase fragment in the Family X Polymerases. The palm in this family contains three aspartic acid motifs. The fingers in this family have Helices M and N that contain amino acid residues. | The thumb, palm, and fingers subdomains are a part of the of N-terminal, or 31-kDA polymerase fragment in the Family X Polymerases. The palm in this family contains three aspartic acid motifs. The fingers in this family have Helices M and N that contain amino acid residues. <ref>DOI: 10.1016/j.bbapap.2009.07.008</ref> | ||
===Family Y=== | ===Family Y=== | ||
The N-terminal of the Family Y polymerases contains the catalytic core of the fingers, palm, and thumb. The C-terminal, which has a conserved tertiary structure of a four-stranded beta sheet supported on one side by two alpha helices, otherwise referred to as the little finger domain, contributes to DNA binding and is essential for complete polymerase activity. This family lacks flexibility in the fingers subdomain, which is uncharacteristic of the other families. The other parts of teh catalytic core and the little finger domain are flexible and frequently assume different positions. | The N-terminal of the Family Y polymerases contains the catalytic core of the fingers, palm, and thumb. The C-terminal, which has a conserved tertiary structure of a four-stranded beta sheet supported on one side by two alpha helices, otherwise referred to as the little finger domain, contributes to DNA binding and is essential for complete polymerase activity. This family lacks flexibility in the fingers subdomain, which is uncharacteristic of the other families. The other parts of teh catalytic core and the little finger domain are flexible and frequently assume different positions. <ref> DOI: 10.1016/j.bbapap.2010.01.020</ref> | ||
