Preferential condensation of SAR-DNA by histone H1 and its SPKK containing octapeptide repeat motif.
Linker histone H1 binds preferentially the scaffold associated region (SAR) DNA elements that contain characteristic oligo dA x dT tracts. In the present study, we have compared the condensation brought about by histone H1 of a SAR DNA fragment in the histone spacer region of Drosophila melanogaster with that of a random DNA (pBR322 EcoRI-SalI) fragment by circular dichroism spectroscopy. The condensation of the SAR DNA fragment by histone H1 is 3-4-fold higher than that of the random DNA fragment. A 16-mer peptide, ATPKKSTKKTPKKAKK, the sequence that is present in the C-terminus of histone Hld, which has recently been shown to possess DNA and chromatin condensing properties, also condenses the SAR DNA fragment preferentially in a highly cooperative manner. We have proposed a model for the dynamics of chromatin structure involving histone H1-SAR DNA interaction through SPKK containing peptide motifs and its competition by AT-hook peptides present in the nonhistone chromosomal proteins like HMG-I and HMG-Y.
Khadake
J R
JR
Department of Biochemistry, Indian Institute of Science, Bangalore, India.
Rao
M R
MR
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004331:Drosophila melanogaster; D006657:Histones / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D011067:Poly dA-dT / Q000378:metabolism*; D051381:Rats
D006657:Histones; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; C016023:oligo(dA-dT); D011067:Poly dA-dT; D004247:DNA