Mapping the interaction surface of linker histone H1(0) with the nucleosome of native chromatin in vivo.
H1 linker histones stabilize the nucleosome, limit nucleosome mobility and facilitate the condensation of metazoan chromatin. Here, we have combined systematic mutagenesis, measurement of in vivo binding by photobleaching microscopy, and structural modeling to determine the binding geometry of the globular domain of the H1(0) linker histone variant within the nucleosome in unperturbed, native chromatin in vivo. We demonstrate the existence of two distinct DNA-binding sites within the globular domain that are formed by spatial clustering of multiple residues. The globular domain is positioned via interaction of one binding site with the major groove near the nucleosome dyad. The second site interacts with linker DNA adjacent to the nucleosome core. Multiple residues bind cooperatively to form a highly specific chromatosome structure that provides a mechanism by which individual domains of linker histones interact to facilitate chromatin condensation.
Brown
David T
DT
Department of Biochemistry, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
Izard
Tina
T
Misteli
Tom
T
D000595:Amino Acid Sequence; D000818:Animals; D041702:BALB 3T3 Cells; D001665:Binding Sites; D036681:Fluorescence Recovery After Photobleaching; D006657:Histones / Q000737:chemistry* / Q000378:metabolism*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009707:Nucleosomes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011993:Recombinant Fusion Proteins / Q000378:metabolism
D006657:Histones; D009707:Nucleosomes; D011993:Recombinant Fusion Proteins