Effect of divalent and monovalent cations on calf thymus PCNA-independent DNA polymerase delta and its 3'----5' exonuclease.
Recent data suggest that DNA polymerases alpha and delta might have a coordinate functional role at the replication fork. In this communication we show that Mg2+ is likely the natural metal activator for both enzymes. Mn2+, a known mutagenic agent, is a competitive inhibitor of Mg2+ for DNA polymerase delta and acompetitive for DNA polymerase alpha. The 3'----5' exonuclease activity associated with DNA polymerase delta is not affected upon addition of Mn2+. Be2+, another mutagenic agent, on the other hand, has an inhibitory effect on the 3'----5' exonuclease, but not on the DNA polymerase delta. The data presented might explain the mutagenic and carcinogenic potential of these two divalent cations.
Focher
F
F
Istituto di Genetica Biochimica ed Evoluzionistica, CNR, Pavia, Italy.
Verri
A
A
Maga
G
G
Spadari
S
S
Hübscher
U
U
D000818:Animals; D002413:Cations, Divalent; D002414:Cations, Monovalent; D002417:Cattle; D004257:DNA Polymerase II / Q000302:isolation & purification / Q000378:metabolism; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase / Q000302:isolation & purification / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D007700:Kinetics; D009687:Nuclear Proteins / Q000502:physiology*; D018809:Proliferating Cell Nuclear Antigen; D013950:Thymus Gland / Q000201:enzymology*
D002413:Cations, Divalent; D002414:Cations, Monovalent; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D004257:DNA Polymerase II; D004258:DNA Polymerase III; D004259:DNA-Directed DNA Polymerase; D004706:Endodeoxyribonucleases; C026044:deoxyribonuclease V