Abstract
The discovery of extremophiles has enabled development of groundbreaking biotechnology. While most of the extremophile research is focused on thermophiles, organisms that adapt to living in cold temperature, known as psychrophiles, remain under-studied. We expressed and purified DNA polymerases PIPI and PIPB from Psychromonas ingrahamii, a psychrophile that can grow below water’s freezing temperature. We demonstrate that they have in vitro DNA replication activity at temperatures as low as −19°C. To our knowledge, this is the coolest DNA polymerization reaction ever carried out in a laboratory. In exploring the behavior of a variety of polymerases as a function of temperature, we found that reaction temperature substantially increases substitution and deletion error rates of both psychrophilic and mesophilic DNA polymerases. Motif analysis further reveals that the substitution error profiles cluster according to phylogenetic similarity of polymerases. Our results provide a useful reference for how reaction temperature, a crucial parameter of biochemistry, can affect the fidelity of DNA polymerases adapted to a wide range of environment.
Competing Interest Statement
The authors have declared no competing interest.
