Skip to content
Login Register

#DNA polymerase V

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 V is part of

Severe DNA damage causes accumulation of single-stranded DNA activating RecA to stimulate autocleavage of LexA repressor derepressing over 40 SOS genes regulon. Among strongly induced are umuD and umuC genes encoding Pol V, Y-family error-prone polymerase capable of copying past pyrimidine dimers that block Pol III. Pol V requires RecA nucleoprotein filament for activation as mutasome complex. Its expression relatively late in SOS response provides last-resort translesion synthesis when excision repair incomplete enabling survival despite persisting lesions but dramatically increasing mutation

Ref: Lewin Genes XII, Chapter 16: SOS response induction of Pol V UmuC-D for translesion synthesis

View Details