DNA polymerase: Difference between revisions

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Alexander Berchansky, David Canner, Michal Harel, Joel L. Sussman, Cori Damron, Emily Bray, Jaime Prilusky

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 ===Reverse Transcriptase===
 See [[Reverse transcriptase]].
+==Structure==
+The basic structure of all DNA polymerases consists of subdomains referred to as the palm, fingers, and thumb. The palm contains catalytically essential amino acids in it's active sites. The fingers are essential for nucleotide recognition and binding. The thumb is important for the binding of the DNA substrate. These subdomains, along with other subdomains specific to each family, are essential for the correct functioning of DNA polymerase.
+===Family A===
+In addition to the basic structure of DNA polymerase, the Family A polymerases also have a subdomain of a 3'-5' vestigial exonuclease. This part of the structure is responsible for proofreading the DNA.
+===Family B===
+In addition to the basic structure of DNA polymerase, the Family B polymerases contain a 3'-5' exonuclease. This is similar to the Family A polymerases.
+===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.
+===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.