PCR performance of the B-type DNA polymerase from the thermophilic euryarchaeon Thermococcus aggregans improved by mutations in the Y-GG/A motif.

ABSTRACT: The effect of mutations in the highly conserved Y-GG/A motif of B-type DNA polymerases was studied in the DNA polymerase from the hyperthermophilic euryarchaeon Thermococcus aggregans. This motif plays a critical role in the balance between the synthesis and degradation of the DNA chain. Five different mutations of the tyrosine at position 387 (Tyr387-->Phe, Tyr387-->Trp, Tyr387-->His, Tyr387-->Asn and Tyr387-->Ser) revealed that an aromatic ring system is crucial for the synthetic activity of the enzyme. Amino acids at this position lacking the ring system (Ser and Asn) led to a significant decrease in polymerase activity and to enhanced exonuclease activity, which resulted in improved enzyme fidelity. Exchange of tyrosine to phenylalanine, tryptophan or histidine led to phenotypes with w

SUBMITTER: Bohlke K 

PROVIDER: S-EPMC110800 | biostudies-literature | 2000 Oct

REPOSITORIES: biostudies-literature