A human centromere protein, CENP-B, has a DNA binding domain containing four potential alpha helices at the NH2 terminus, which is separable from dimerizing activity.
The alphoid DNA-CENP-B (centromere protein B) complex is the first sequence-specific DNA/protein complex detected in the centromeric region of human chromosomes. In the reaction, CENP-B recognizes a 17-bp sequence (CENP-B box) and assembles two alphoid DNA molecules into a complex, which is designated complex A (Muro, Y., H. Masumoto, K. Yoda, N. Nozaki, M. Ohashi, and T. Okazaki. 1992. J. Cell Biol. 116:585-596). Since CENP-B gene is conserved in mammalian species and CENP-B boxes are found also in mouse centromere satellite DNA (minor satellite), this sequence-specific DNA-protein interaction may be important for some kind of common centromere function. In this study we have characterized the structure of CENP-B and CENP-B-alphoid DNA complex. We have shown by chemical cross-linking that CENP-B formed a dimer, and have estimated by molecular weight determination the composition of complex A to be a CENP-B dimer and two molecules of alphoid DNA. The DNA binding domain has been delimited within the NH2-terminal 125-amino acid region containing four potential alpha-helices using truncated CENP-B made in Escherichia coli cells. We have shown that CENP-B had sites highly sensitive to proteases and that the DNA binding domain was separable from the dimerizing activity by the proteolytic cleavage at 20 kD from the COOH terminus of the molecule. Thus, CENP-B may organize a higher order structure in the centromere by juxtaposing two CENP-B boxes in the alphoid DNA repeat through both the DNA-protein and protein-protein interactions.
Yoda
K
K
Department of Molecular Biology, School of Science, Nagoya University, Japan.
Kitagawa
K
K
Masumoto
H
H
Muro
Y
Y
Okazaki
T
T
D000595:Amino Acid Sequence; D001324:Autoantigens; D001483:Base Sequence; D002503:Centromere / Q000737:chemistry*; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone / Q000187:drug effects / Q000378:metabolism*; D003432:Cross-Linking Reagents; D004247:DNA / Q000378:metabolism; D004252:DNA Mutational Analysis; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000378:metabolism*; D010450:Endopeptidases / Q000494:pharmacology; D004926:Escherichia coli / Q000235:genetics; D005976:Glutaral; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010446:Peptide Fragments / Q000378:metabolism; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000187:drug effects / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
D001324:Autoantigens; C497926:CENPB protein, human; D051936:Centromere Protein B; D002868:Chromosomal Proteins, Non-Histone; D003432:Cross-Linking Reagents; D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011994:Recombinant Proteins; D004247:DNA; D010450:Endopeptidases; D005976:Glutaral