Skip to content
Login Register

#DNA polymerase IV

2 public questions tagged with this topic.

Repair Pathway

DNA Pol IV and V belong to which polymerase family?

Escherichia coli DNA polymerases IV encoded by dinB and V encoded by umuD'2C belong to Y-family of translesion polymerases, distinct from canonical A-family, B-family replicases, and X-family repair enzymes. Y-family members share unique structural features including little finger domain, unusually open solvent-accessible active site that accommodates bulky lesions such as benzo[a]pyrene adducts and thymine dimers, and absence of proofreading domain. They display low processivity, synthesizing only few nucleotides per binding event. Evolutionary conservation includes human Pol eta, iota, kappa

Ref: Lehninger Principles of Biochemistry, 8th ed., Chapter 27: Y-family polymerase structural features; EMBO J 1999 Pol IV V identification

View Details
Replication in Prokaryotes

DNA polymerase IV is involved in

When Pol III encounters blocking lesions like thymine dimers or apurinic sites, replication forks stall because high-fidelity active site cannot accommodate distorted template geometry. Specialized Y-family polymerases bypass damage continuing replication. Pol IV encoded by dinB gene and related Pol V are induced as part of SOS response. Pol IV performs translesion synthesis across various N2-dG adducts and alkylation lesions with lower fidelity allowing continuation at cost of increased mutagenesis. It lacks proofreading and inserts nucleotides opposite lesion where replicative enzyme cannot,

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 5: SOS and translesion polymerases Pol IV and V

View Details