Initial crystallographic study of human PCNA in complex with a peptide containing the noncanonical PIP-box sequence of human DNA polymerase ι

Human DNA polymerase iota (Pol iota) is one of the Y-family DNA polymerases involved in translesion synthesis (TLS), which allows continued replication at damaged DNA templates. Pol iota has a noncanonical PCNA-interacting protein box (PIP-box) within an internal region of the protein. Pol iota activity is stimulated by PCNA binding through the noncanonical PIP-box. To clarify the interaction of PCNA with the noncanonical PIP-box of Pol iota, PCNA and a Pol iota peptide carrying the noncanonical PIP-box complex have been cocrystallized. The crystal belongs to space group C2, with unit-cell parameters a = 167.1, b = 68.7, c = 90.0 angstrom, beta = 95.1 degrees. Structural analysis by molecular replacement is in progress.