title: The N-terminal basic domain of human parvulin hPar14 is responsible for the entry to the nucleus and high-affinity DNA-binding.
abstract: We have studied the cellular localization and the DNA-binding capability of human peptidyl-prolyl cis/trans isomerase hPar14. The cellular expression pattern shows an uneven distribution of the protein between cytoplasm and nucleus. To determine the nuclear localization of hPar14 in vivo the molecule was fused to green fluorescent protein and expressed in human HeLa cells. Deletion mutants of hPar14 were used to restrict a sequence, necessary for nuclear targeting, to Ser7-Lys14 of the N terminus of the protein. DNA-cellulose affinity experiments were performed to demonstrate that hPar14, which is present in the nuclear fraction, could bind to double-stranded native DNA in vitro. On the basis of homologies and similarities of hPar14 to members of the high-mobility group proteins, double-stranded DNA constructs were developed and tested for their hPar14 binding affinity in fluorescence titration assays. The protein binds preferentially to bent A-tract sequences. The binding interface of the protein was determined by 1-D and 2-D NMR studies of the complex of unlabeled DNA and uniformly 15N-labeled hPar14((1-131)). Experiments with a truncated hPar14((25-131)) showed that the unstructured N-terminal 25 amino acid residues are necessary for high-affinity binding to DNA. These findings in connection with sequence and structural homologies of hPar14 to members of the HMGB/HMGN protein family suggest a function of hPar14 in cell-cycle regulation or gene transcription.
authors.affiliation: Max Planck Research Unit for Enzymology of Protein Folding, Weinberg 22, Halle/Saale, Germany.
authors.forename: Tatiana Anna
authors.initials: TA
authors.lastname: Surmacz
authors.forename: Elena
authors.initials: E
authors.lastname: Bayer
authors.forename: Jens Ulrich
authors.initials: JU
authors.lastname: Rahfeld
authors.forename: Gunter
authors.initials: G
authors.lastname: Fischer
authors.forename: Peter
authors.initials: P
authors.lastname: Bayer
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism*; D002482:Cellulose / Q000031:analogs & derivatives*; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D005260:Female; D005453:Fluorescence; D006367:HeLa Cells; D006609:High Mobility Group Proteins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D009994:Osmolar Concentration; D019696:Peptidylprolyl Isomerase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011993:Recombinant Fusion Proteins; D017384:Sequence Deletion
chemical_list: D004268:DNA-Binding Proteins; C033190:DNA-cellulose; D006609:High Mobility Group Proteins; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D011993:Recombinant Fusion Proteins; D002482:Cellulose; D004247:DNA; C000606846:PIN1 protein, human; D019696:Peptidylprolyl Isomerase