Τίτλος:
PCR performance of the B-type DNA polymerase from the thermophilic
euryarchaeon Thermococcus aggregans improved by mutations in the Y-GG/A
motif
Γλώσσες Τεκμηρίου:
Αγγλικά
Περίληψη:
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, Tyr381–>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 wild-type-like fidelity
but enhanced PCR performance that could be related to a higher velocity
of polymerisation. With the help of a modelled structure of T.aggregans
DNA polymerase, the biochemical data were interpreted proposing that the
conformation of the flexible loop containing the Y-GG/A motif is an
important factor for the equilibrium between DNA polymerisation and
exonucleolysis.
Συγγραφείς:
Bohlke, K
Pisani, FM
Vorgias, CE
Frey, B
Sobek, H and
Rossi, M
Antranikian, G
Περιοδικό:
Nucleic Acids Research
Εκδότης:
Oxford University Press
DOI:
10.1093/nar/28.20.3910
