The maize chromosomal HMGa protein recognizes structural features of DNA and increases DNA flexibility.
The abundant maize high-mobility group protein HMGa belongs to the chromosomal, non-histone proteins and consists of a basic region containing the HMG-box DNA-binding domain and a highly acidic carboxy-terminal tail. The full-length HMGa protein and a truncated version lacking the acidic tail were synthesized in Escherichia coli and tested for their ability to induce DNA-bending in a ligase mediated circularization assay with short DNA fragments. It is shown that the recombinant HMGa protein as well as its truncated form efficiently cause circularization of the tested DNA fragments without an obvious requirement for stable DNA-binding. They bind furthermore preferentially to A/T-rich linear DNA or bent DNA structures such as four-way junctions and DNA minicircles. The DNA-binding properties and the ability to increase DNA flexibility suggest a general role of the HMGa protein in assisting the formation of nucleoprotein complexes, possibly by facilitating interactions of proteins bound to adjacent DNA sites.
Grasser
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KD
Institut für Biologie III, Albrecht-Ludwigs-Universität, Freiburg, Germany.
Krech
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AB
Feix
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G
D001483:Base Sequence; D017931:DNA Primers; D018744:DNA, Plant / Q000378:metabolism*; D004926:Escherichia coli; D006609:High Mobility Group Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011994:Recombinant Proteins / Q000378:metabolism; D003313:Zea mays / Q000378:metabolism
D017931:DNA Primers; D018744:DNA, Plant; D006609:High Mobility Group Proteins; D011994:Recombinant Proteins