title: AtMSI4 and RbAp48 WD-40 repeat proteins bind metal ions.
abstract: The mammalian RbAp48 protein is the most extensively studied member of the conserved family of Msi1-like WD-40 repeat proteins, which are components of complexes involved in the assembly and modification of chromatin. We have isolated a plant homolog of RbAp48, AtMSI4. By metal affinity chromatography, zinc blotting and atomic absorption analysis, we demonstrate that purified recombinant RbAp48 and AtMSI4 proteins bind 3-4 metal ions per molecule of protein. Metal competition assays indicate a preference for zinc. Both N- and C-terminal halves of RbAp48 and AtMSI4 display zinc binding activity, suggesting it is an intrinsic property of the propeller structures likely to be formed by these proteins. Metal binding might mediate and/or regulate protein-protein interactions which are functionally important in chromatin metabolism.
authors.affiliation: Department of Biochemistry, University of Missouri-Columbia, 65211, USA.
authors.forename: A L
authors.initials: AL
authors.lastname: Kenzior
authors.forename: W R
authors.initials: WR
authors.lastname: Folk
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002846:Chromatography, Affinity; D008670:Metals / Q000378:metabolism*; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000302:isolation & purification / Q000378:metabolism*; D010940:Plant Proteins / Q000302:isolation & purification / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors; D015032:Zinc / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D002352:Carrier Proteins; C116635:MSI4 protein, Arabidopsis; D008670:Metals; D009687:Nuclear Proteins; D010940:Plant Proteins; D014157:Transcription Factors; D015032:Zinc