| DNA-directed DNA polymerase | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Identifiers | |||||||||
| EC no. | 2.7.7.7 | ||||||||
| CAS no. | 9012-90-2 | ||||||||
| Databases | |||||||||
| IntEnz | IntEnz view | ||||||||
| BRENDA | BRENDA entry | ||||||||
| ExPASy | NiceZyme view | ||||||||
| KEGG | KEGG entry | ||||||||
| MetaCyc | metabolic pathway | ||||||||
| PRIAM | profile | ||||||||
| PDB structures | RCSB PDBPDBePDBsum | ||||||||
| |||||||||
DNA polymerase alpha, also known asPol α, is anenzyme complex found ineukaryotes that is involved in initiation ofDNA replication. The DNA polymerase alpha complex consists of 4 subunits:POLA1,POLA2,PRIM1, andPRIM2.[2]
Pol α has limitedprocessivity and lacks 3′exonuclease activity for proofreading errors. Thus it is not well suited to efficiently and accurately copy long templates (unlike PolDelta andEpsilon). Instead, it plays a more limited role in replication. Pol α is responsible for the initiation of DNA replication at origins of replication (on both the leading and lagging strands) and during synthesis ofOkazaki fragments on the lagging strand. The Pol α complex (pol α-DNA primase complex) consists of four subunits: the catalytic subunit POLA1, the regulatory subunitPOLA2, and the small and the large primase subunits PRIM1 and PRIM2 respectively. Once primase has created the RNA primer, Pol α starts replication elongating the primer with ~20 nucleotides.[2]
DNA polymerase alpha, likeDNA primase, contains iron-sulfur clusters, that are critical inelectron transport that uses DNA itself to transfer electrons at very high speeds; this process is involved in detecting DNA damage, and may also be involved in a feedback between the primase complex and the DNA polymerase alpha.[3]
This article incorporates text from theUnited States National Library of Medicine, which is in thepublic domain.
