DsqP

DsqP, also known as the deoxyguanosine triphosphate (dGTP) triphosphohydrolase DsqP, is a protein involved in DNA repair. It is a nucleoside triphosphate hydrolase that catalyzes the hydrolysis of dGTP to deoxyguanosine monophosphate (dGMP) and pyrophosphate. This activity is crucial for preventing the accumulation of dGTP, which can lead to an increased mutation rate by being misincorporated into DNA. DsqP is conserved across a wide range of organisms, including bacteria and archaea.

The DsqP protein plays a role in maintaining genomic stability. By hydrolyzing excess dGTP, it ensures that the cellular pool of deoxyguanosine triphosphates is maintained at appropriate levels. High concentrations of dGTP can result in increased frequency of G to T transversions during DNA replication due to its structural similarity to dATP, which can be mispaired with thymine. Therefore, DsqP acts as a safeguard against such potentially deleterious mutations.

In some bacteria, DsqP has been linked to the SOS response, a global regulatory network induced by DNA damage. Its precise role within this complex pathway is still an area of ongoing research, but it is believed to contribute to the overall cellular defense against genotoxic stress. The enzyme's structure reveals a typical nucleoside triphosphate hydrolase fold, with active site residues crucial for its catalytic function. Understanding DsqP's mechanism and regulation can provide insights into fundamental DNA repair processes.