PURDNA/RNA-binding repeats in PUR-alpha/beta/gamma and in hypothetical proteins from spirochetes and the Bacteroides-Cytophaga-Flexibacter bacteria. |
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| SMART accession number: | SM00712
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| Description: |
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| Interpro abstract (IPR006628): |
The Pur protein family consists of four known members in humans and is strongly conserved throughout evolution. Pur-alpha is a highly conserved, sequence-specific DNA- and RNA-binding protein involved in diverse cellular and viral functions including transcription, replication, and cell growth. Pur-alpha has a modular structure with alternating three basic aromatic class I and two acidic leucine-rich class II repeats in the central region of the protein [(PUBMED:1448097)]. In addition to its involved in basic cellular function, Pur-alpha, has been implicated in the development of blood cells and cells of the central nervous system; it has also been implicated in the inhibition of oncogenic transformation and along with Pur-beta in myelodysplastic syndrome progressing to acute myelogenous leukemia. Pur-alpha can influence viral interaction through functional associations, for example with the Tat protein and TAR RNA of HIV-1, and with large T-antigen and DNA regulatory regions of JC virus. JC virus causes opportunistic infections in the brains of certain HIV-1-infected individuals [(PUBMED:12894583)].
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| Family alignment: |
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There are 380
PUR domains in 136 proteins in SMART's nrdb database.
Click on the following links for more information.
- Evolution (species in which this domain is found)
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- Cellular role (predicted cellular role)
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Binding / catalysis: DNA/RNA-binding
- Literature (relevant references for this domain)
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Primary literature is listed below; Automatically-derived, secondary literature is also avaliable.
- Grishin NV
- The R3H motif: a domain that binds single-stranded nucleic acids.
- Trends Biochem Sci. 1998; 23: 329-30
- Johnson EM et al.
- Association of human Pur alpha with the retinoblastoma protein, Rb,regulates binding to the single-stranded DNA Pur alpha recognitionelement.
- J Biol Chem. 1995; 270: 24352-60
- Display abstract
The retinoblastoma protein, Rb, is detected in extracts of monkey CV-1cells complexed with Pur alpha, a sequence-specific single-strandedDNA-binding protein implicated in control of gene transcription and DNAreplication. These complexes can be immunoextracted from cell lysatesusing monoclonal antibodies to either Pur alpha or Rb. The Pur alpha-Rbcomplexes contain a form of Pur alpha with extensive post-syntheticmodification, as demonstrated following expression of Pur alpha cDNA fusedto a 9-amino acid epitope tag. Human Pur alpha, expressed as a glutathioneS-transferase fusion protein, specifically binds to the hypophosphorylatedform of Rb with an affinity as high as that of SV40 large T-antigen. Inthe absence of DNA, glutathione S-transferase-Pur alpha binds to p56RB, anNH2-terminal-truncated Rb protein purified from Escherichia coli,containing the T-antigen binding domain, to form multimeric complexes. Thesingle-stranded DNA Pur alpha recognition element disrupts thesecomplexes. Conversely, high concentrations of p56RB prevent Pur alphabinding to DNA. Through use of a series of deletion mutants, the DNAbinding activity of Pur alpha is localized to a series of modular aminoacid repeats. Rb binding involves a Pur alpha region with limited homologyto the Rb-binding region of SV40 large T-antigen. Binding of Pur alpha top56RB, the COOH-terminal portion of Rb, is inhibited by a syntheticpeptide containing the T-antigen Rb-binding motif.
- Bergemann AD, Ma ZW, Johnson EM
- Sequence of cDNA comprising the human pur gene and sequence-specificsingle-stranded-DNA-binding properties of the encoded protein.
- Mol Cell Biol. 1992; 12: 5673-82
- Display abstract
The human Pur factor binds strongly to a sequence element repeated withinzones of initiation of DNA replication in several eukaryotic cells. Theprotein binds preferentially to the purine-rich single strand of thiselement, PUR. We report here the cloning and sequencing of a cDNA encodinga protein with strong affinity for the PUR element. Analysis with a seriesof mutated oligonucleotides defines a minimal single-stranded DNAPur-binding element. The expressed Pur open reading frame encodes aprotein of 322 amino acids. This protein, Pur alpha, contains threerepeats of a consensus motif of 23 amino acids and two repeats of a secondconsensus motif of 26 amino acids. Near its carboxy terminus, the proteinpossesses an amphipathic alpha-helix and a glutamine-rich domain. Therepeat region of Pur cDNA is homologous to multiple mRNA species in eachof several human cell lines and tissues. The HeLa cDNA library alsoincludes a clone encoding a related gene, Pur beta, containing a versionof the 23-amino-acid consensus motif similar, but not identical, to thosein Pur alpha. Results indicate a novel type of modular protein withcapacity to bind repeated elements in single-stranded DNA.
- Structure (3D structures containing this domain)
3D Structures of PUR domains in PDB
| PDB code | Main view | Title | | 3k44 |  | Crystal structure of drosophila melanogaster pur-alpha |
- Links (links to other resources describing this domain)
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