Recombinant Human POLL protein

**Background of POLL (DNA Polymerase Lambda) Recombinant Protein**

POLL, or DNA polymerase lambda, is a member of the X-family of DNA polymerases, which play critical roles in DNA repair and genome maintenance. Discovered in the early 2000s, POLL shares structural and functional similarities with other X-family polymerases, such as Pol β, but exhibits distinct substrate preferences and enzymatic properties. It is encoded by the *POLL* gene in humans and is primarily involved in base excision repair (BER), non-homologous end joining (NHEJ), and translesion synthesis (TLS), processes essential for correcting DNA damage caused by oxidative stress, alkylating agents, or ionizing radiation.

Structurally, POLL contains a conserved polymerase core domain and a C-terminal BRCT domain, facilitating interactions with other repair proteins. Unlike some polymerases, POLL lacks intrinsic proofreading activity but demonstrates high fidelity in specific contexts, particularly during gap-filling synthesis in short-patch BER. Its ability to process mismatched primer-template structures and incorporate nucleotides across damaged DNA makes it a versatile player in maintaining genomic stability.

Recombinant POLL protein is produced using biotechnological platforms, such as *E. coli* or mammalian expression systems, enabling large-scale purification for functional studies. Researchers employ it to investigate its enzymatic kinetics, structural dynamics, and interactions with DNA repair complexes. Recombinant POLL has also been utilized in diagnostic assays and drug discovery, particularly in targeting DNA repair pathways for cancer therapy.

Emerging studies highlight POLL's dual role in both promoting genome integrity and contributing to mutagenesis under stress, underscoring its therapeutic relevance. Its recombinant form remains a vital tool for dissecting DNA repair mechanisms and developing strategies to modulate these pathways in disease contexts.