title: Structural and thermodynamic analysis of human PCNA with peptides derived from DNA polymerase-delta p66 subunit and flap endonuclease-1.
abstract: Human Proliferating Cellular Nuclear Antigen (hPCNA), a member of the sliding clamp family of proteins, makes specific protein-protein interactions with DNA replication and repair proteins through a small peptide motif termed the PCNA-interacting protein, or PIP-box. We solved the structure of hPCNA bound to PIP-box-containing peptides from the p66 subunit of the human replicative DNA polymerase-delta (452-466) at 2.6 A and of the flap endonuclease (FEN1) (331-350) at 1.85 A resolution. Both structures demonstrate that the pol-delta p66 and FEN1 peptides interact with hPCNA at the same site shown to bind the cdk-inhibitor p21(CIP1). Binding studies indicate that peptides from the p66 subunit of the pol-delta holoenzyme and FEN1 bind hPCNA from 189- to 725-fold less tightly than those of p21. Thus, the PIP-box and flanking regions provide a small docking peptide whose affinities can be readily adjusted in accord with biological necessity to mediate the binding of DNA replication and repair proteins to hPCNA.
authors.affiliation: Department of Biochemistry and Cell Biology, Rice University, 6100 South Main Street, MS140, Houston, TX 77005, USA.
authors.forename: John B
authors.initials: JB
authors.lastname: Bruning
authors.forename: Yousif
authors.initials: Y
authors.lastname: Shamoo
mesh_terms: D002151:Calorimetry; D003460:Crystallization; D004258:DNA Polymerase III / Q000378:metabolism*; D045585:Flap Endonucleases / Q000378:metabolism*; D006801:Humans; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D018809:Proliferating Cell Nuclear Antigen / Q000737:chemistry* / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013816:Thermodynamics
chemical_list: D010446:Peptide Fragments; D018809:Proliferating Cell Nuclear Antigen; C435720:POLD3 protein, human; D004258:DNA Polymerase III; D045585:Flap Endonucleases