6hvo
Crystal structure of human PCNA in complex with three peptides of p12 subunit of human polymerase delta
Structural highlights
FunctionPCNA_HUMAN Auxiliary protein of DNA polymerase delta and is involved in the control of eukaryotic DNA replication by increasing the polymerase's processibility during elongation of the leading strand. Induces a robust stimulatory effect on the 3'-5' exonuclease and 3'-phosphodiesterase, but not apurinic-apyrimidinic (AP) endonuclease, APEX2 activities. Has to be loaded onto DNA in order to be able to stimulate APEX2. Plays a key role in DNA damage response (DDR) by being conveniently positioned at the replication fork to coordinate DNA replication with DNA repair and DNA damage tolerance pathways. Acts as a loading platform to recruit DDR proteins that allow completion of DNA replication after DNA damage and promote postreplication repair: Monoubiquitinated PCNA leads to recruitment of translesion (TLS) polymerases, while 'Lys-63'-linked polyubiquitination of PCNA is involved in error-free pathway and employs recombination mechanisms to synthesize across the lesion.[1] [2] Publication Abstract from PubMedHuman DNA polymerase delta is essential for DNA replication and acts in conjunction with the processivity factor proliferating cell nuclear antigen (PCNA). Besides its catalytic subunit (p125), pol delta comprises three regulatory subunits (p50, p68, and p12). PCNA interacts with all of these subunits, but only the interaction with p68 has been structurally characterized. Here, we report solution NMR-, isothermal titration calorimetry-, and X-ray crystallography-based analyses of the p12-PCNA interaction, which takes part in the modulation of the rate and fidelity of DNA synthesis by pol delta. We show that p12 binds with micromolar affinity to the classical PIP-binding pocket of PCNA via a highly atypical PIP-box located at the p12 N terminus. Unlike the canonical PIP-box of p68, the PIP-box of p12 lacks the conserved glutamine, binds through a 2-fork plug made of an isoleucine and a tyrosine residue at +3 and +8 positions, respectively, and is stabilized by an aspartate at +6 position, which creates a network of intra-molecular hydrogen bonds. These findings add to growing evidence that PCNA can bind a diverse range of protein sequences that may be broadly grouped as PIP-like motifs as has been previously suggested. The p12 subunit of human polymerase delta uses an atypical PIP-box for molecular recognition of proliferating cell nuclear antigen (PCNA).,Gonzalez-Magana A, Ibanez de Opakua A, Romano-Moreno M, Murciano-Calles J, Merino N, Luque I, Rojas AL, Onesti S, Blanco FJ, De Biasio A J Biol Chem. 2019 Jan 17. pii: RA118.006391. doi: 10.1074/jbc.RA118.006391. PMID:30655288[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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