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DNA polymerase alpha

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(Redirected from Polymerase (DNA directed), alpha 1) Family of protein complexes
DNA-directed DNA polymerase
Identifiers
EC no.2.7.7.7
CAS no.9012-90-2
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MetaCycmetabolic pathway
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NCBIproteins
Shared primase-binding peptide in archaeal PolD and eukaryotic Polα

DNA polymerase alpha also known as Pol α is an enzyme complex found in eukaryotes that is involved in initiation of DNA replication. The DNA polymerase alpha complex consists of 4 subunits: POLA1, POLA2, PRIM1, and PRIM2.

Pol α has limited processivity and lacks 3′ exonuclease activity for proofreading errors. Thus it is not well suited to efficiently and accurately copy long templates (unlike Pol Delta and Epsilon). 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 of Okazaki fragments on the lagging strand. The Pol α complex (pol α-DNA primase complex) consists of four subunits: the catalytic subunit POLA1, the regulatory subunit POLA2, 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.

Structure

DNA polymerase alpha, like DNA primase, contains iron-sulfur clusters, that are critical in electron 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.

References

  1. Madru, Clément; Henneke, Ghislaine; Raia, Pierre; Hugonneau-Beaufet, Inès; Pehau-Arnaudet, Gérard; England, Patrick; Lindahl, Erik; Delarue, Marc; Carroni, Marta; Sauguet, Ludovic (December 2020). "Structural basis for the increased processivity of D-family DNA polymerases in complex with PCNA". Nature Communications. 11 (1): 1591. doi:10.1038/s41467-020-15392-9. PMC 7101311.
  2. ^ Lehman IR, Kaguni LS (March 1989). "DNA polymerase alpha" (PDF). J. Biol. Chem. 264 (8): 4265–8. doi:10.1016/S0021-9258(18)83733-4. PMID 2647732.
  3. "Electrons use DNA like a wire for signaling DNA replication".

External links

DNA replication (comparing prokaryotic to eukaryotic)
Initiation
Prokaryotic
(initiation)
Eukaryotic
(preparation in
G1 phase
)
Both
Replication
Prokaryotic
(elongation)
Eukaryotic
(synthesis in
S phase
)
Both
Termination
Transferases: phosphorus-containing groups (EC 2.7)
2.7.1-2.7.4:
phosphotransferase/kinase
(PO4)
2.7.1: OH acceptor
2.7.2: COOH acceptor
2.7.3: N acceptor
2.7.4: PO4 acceptor
2.7.6: diphosphotransferase
(P2O7)
2.7.7: nucleotidyltransferase
(PO4-nucleoside)
Polymerase
DNA polymerase
DNA-directed DNA polymerase
I/A
γ
θ
ν
T7
Taq
II/B
α
δ
ε
ζ
Pfu
III/C
IV/X
β
λ
μ
TDT
V/Y
η
ι
κ
RNA-directed DNA polymerase
Reverse transcriptase
Telomerase
RNA polymerase
Template-directed
RNA polymerase I
II
III
IV
V
ssRNAP
POLRMT
Primase
1
2
PrimPol
RNA-dependent RNA polymerase
Polyadenylation
PAP
PNPase
Phosphorolytic
3' to 5' exoribonuclease
Nucleotidyltransferase
Guanylyltransferase
Other
2.7.8: miscellaneous
Phosphatidyltransferases
Glycosyl-1-phosphotransferase
2.7.10-2.7.13: protein kinase
(PO4; protein acceptor)
2.7.10: protein-tyrosine
2.7.11: protein-serine/threonine
2.7.12: protein-dual-specificity
2.7.13: protein-histidine
Enzymes
Activity
Regulation
Classification
Kinetics
Types
Portal:

This article incorporates text from the United States National Library of Medicine, which is in the public domain.


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