Temperature effect on polymerase fidelity

The discovery of extremophiles helped enable the development of
groundbreaking technology such as polymerase chain reaction. Temperature
variation is often an essential step of these technology platforms, but
the effect of temperature on the error rate of polymerases from different
origins is under-explored. We applied high-throughput sequencing to
profile the error rates of DNA polymerases from psychrophilic, mesophilic,
and thermophilic origins with single-molecule resolution. We found that
reaction temperature substantially increases substitution and deletion
error rates of both psychrophilic and mesophilic DNA polymerases. Our
motif analysis shows that the substitution error profiles cluster
according to phylogenetic similarity of polymerases, not reaction
temperature, thus suggesting that reaction temperature increases global
error rate of polymerases independent of sequence context. Intriguingly,
we also found that the DNA polymerase I of a psychrophilic bacteria
exhibits higher polymerization activity than its mesophilic ortholog
across all temperature ranges, including down to -19oC which is well below
water's freezing temperature. Our results provide a useful reference
for how reaction temperature, a crucial parameter of biochemistry, can
affect DNA polymerase fidelity in organisms adapted to a wide range of
thermal environments.