PCNAklammin

PCNAklammin is a fictional protein described in speculative biology and science fiction to regulate the PCNA sliding clamp involved in DNA replication and repair. The name combines PCNA, the proliferating cell nuclear antigen that forms a homotrimeric sliding clamp, with the suffix -klammin to evoke clamp-like function.

In the imagined models, PCNAklammin binds directly to PCNA through a PCNA-interaction motif, and modulates clamp loading or unloading by interacting with RFC or alternative clamp loaders. It is proposed to influence the choice of DNA polymerases at the replication fork and to facilitate switching between high-fidelity and translesion synthesis polymerases in response to DNA damage.

Structural descriptions in fictional sources typically depict PCNAklammin as a small, primarily alpha-helical protein with a conserved PCNA-binding motif. Some accounts suggest it forms a heterotrimeric complex with PCNA, though this varies by author.

Physiological context places PCNAklammin in limited lineages or environmental conditions that stress DNA integrity, often described as being upregulated upon replication stress and participating in repair pathways, including coordination with PCNA ubiquitination pathways in the narrative.

Because PCNAklammin is not recognized in real-world biochemistry, there are no experimental data or peer-reviewed studies. It is primarily used in educational simulations and fiction to illustrate how regulatory factors might interact with sliding clamps.

See also: proliferating cell nuclear antigen, sliding clamp, DNA replication, PCNA-interacting protein motif, RFC.