A Putative DNA Binding Surface in the Globular Domain of a Linker Histone Is Not Essential for Specific Binding to the Nucleosome

A fundamental step in the assembly of native chromatin is the specific recognition and binding of linker histones to the nucleoprotein subunit known as the nucleosome. A first step in defining this important interaction is the determination of residues within linker histones that are important for the structure-specific recognition of the nucleosome core. By combining in vitro assays for the native binding activity of linker histones and site-directed mutagenesis, we have examined a cluster of basic residues within the globular domain of H10, a somatic linker histone variant from Xenopus laevis. We show that these residues, which comprise a putative DNA binding surface within the globular domain, do not play an essential role in the structure-specific binding of a linker histone to the nucleosome. A fundamental step in the assembly of native chromatin is the specific recognition and binding of linker histones to the nucleoprotein subunit known as the nucleosome. A first step in defining this important interaction is the determination of residues within linker histones that are important for the structure-specific recognition of the nucleosome core. By combining in vitro assays for the native binding activity of linker histones and site-directed mutagenesis, we have examined a cluster of basic residues within the globular domain of H10, a somatic linker histone variant from Xenopus laevis. We show that these residues, which comprise a putative DNA binding surface within the globular domain, do not play an essential role in the structure-specific binding of a linker histone to the nucleosome.