title: DNA-binding properties of Arabidopsis MADS domain homeotic proteins APETALA1, APETALA3, PISTILLATA and AGAMOUS.
abstract: The MADS domain proteins APETALA1 (AP1), APETALA3 (AP3), PISTILLATA (PI), and AGAMOUS (AG) specify the identity of Arabidopsis floral organs. AP1 and AG homocomplexes and AP3-PI heterocomplexes bind to CArG-box sequences. The DNA-binding properties of these complexes were investigated. We find that AP1, AG and AP3-PI are all capable of recognizing the same DNA-binding sites, although with somewhat different affinities. In addition, the three complexes induce similar conformational changes on a CArG-box sequence. Phasing analysis reveals that the induced distortion is DNA bending, oriented toward the minor groove. The molecular dissection of AP1, AP3, PI and AG indicates that the boundaries of the dimerization domains of these proteins vary. The regions required to form a DNA-binding complex include, in addition to the MADS box, the entire L region (which follows the MADS box) and the first putative amphipathic helix of the K box in the case of AP3-PI, while for AP1 and AG only a part of the L region is needed. The similarity of the DNA-binding properties of AP1, AP3-PI and AG is discussed with regard to the biological specificity that these proteins exhibit.
authors.affiliation: Division of Biology, California Institute of Technology, Pasadena 91125, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Riechmann
authors.forename: M
authors.initials: M
authors.lastname: Wang
authors.forename: E M
authors.initials: EM
authors.lastname: Meyerowitz
mesh_terms: D026342:AGAMOUS Protein, Arabidopsis; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins; D001483:Base Sequence; D001665:Binding Sites; D015342:DNA Probes / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D018398:Homeodomain Proteins / Q000378:metabolism*; D026161:MADS Domain Proteins; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010940:Plant Proteins / Q000378:metabolism*; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D026342:AGAMOUS Protein, Arabidopsis; C091535:AP1 protein, Arabidopsis; C101342:APETALA 3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D015342:DNA Probes; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D026161:MADS Domain Proteins; C090225:PISTILLATA protein, Arabidopsis; D010940:Plant Proteins; D011994:Recombinant Proteins; D014157:Transcription Factors