DNA polymerase, Y-family, little finger domain (IPR017961)
Short name: DNA_pol_Y-fam_little_finger
Overlapping homologous superfamilies
This entry represents the little finger domain found in Y-family (lesion bypass) DNA polymerases. Y-family polymerases were originally known as UmuC/DinB/Rev1/Rad30 after each branch of the family. These enzymes are characterised by their low-fidelity synthesis on undamaged DNA templates and by their ability to traverse replication-blocking lesions. By contrast, high-fidelity polymerases (such as DNA polymerase III) are sensitive to distortions in the DNA template. As a result, Y-family polymerases can extend primer strands across DNA strand lesions that would otherwise stall replicative polymerases. To minimize mutations through their low fidelity synthesis, these enzymes are regulated, and are thought to interact with processivity factors, beta-clamp or proliferating cell nuclear antigen (PCNA), which are also essential for the function of replicative DNA polymerases [PMID: 14592985]. Organisms can contain more than one Y-family polymerase, each with a unique DNA damage bypass and fidelity profile. For example, humans posses four Y-family polymerases: DNA polymerases kappa, iota, eta and Rev1. Y-family polymerases show no homology to DNA polymerases from the A-, B-, C-, D- or X-families [PMID: 11595188].
The Y-family of DNA polymerases includes the following enzymes:
- Prokaryotic DNA polymerase IV (DinB) [PMID: 14592985].
- Archaeal DinB homologue DNA polymerase IV [PMID: 11595188].
- Eukaryotic DinB homologue DNA polymerase kappa [PMID: 15296733].
- Prokarytoic DNA repair proteins UmuC and UmuD [PMID: 17207624].
- Eukaryotic Rad30 homologues DNA polymerase eta and iota [PMID: 11545743, PMID: 16819516].
- Eukaryotic DNA repair protein Rev1 [PMID: 18603483].
Human DNA polymerase kappa is a right-handed shaped molecule with palm, fingers, thumb, little finger and wrist subdomains [PMID: 15296733].
- PF11799 (IMS_C)