RESUMO
Human linker histones (H1s) are important in chromatin packaging and condensation. The central globular domain of H1 anchors the protein to the nucleosome. The nucleosomal binding modes of different H1 globular domains may affect nucleosomal DNA accessibility in distinct ways. The globular domain structures of human linker histones H1.0 (GH1.0), H1.4 (GH1.4), H1t (GH1t) and H1oo (GH1oo) were homology modelled and energy minimized. A docking algorithm [validated by re-docking GH5 from the GH5-chromatosome crystal structure (PDB: 4QLC) to the nucleosome] was used to dock the modelled domains to the same nucleosome template. In addition, GH1 (PDB: 1GHC) and a protein consisting of the N-terminal and globular domains of H1x (NGH1x) were also docked using this algorithm. Models of these docked structures are presented here in the form of PDB files. The models can be used to gain more insight with regards to the nucleosomal binding modes of H1s and their individual influence on chromatin compaction.
RESUMO
Linker histone H1 plays a vital role in the packaging of DNA. H1 has a tripartite structure: a conserved central globular domain that adopts a winged-helix fold, flanked by highly variable and intrinsically unstructured N- and C-terminal domains. The datasets presented in this article include raw 2D and 3D BEST-TROSY NMR data [1H-15â¯N HSQC; 15â¯N and 13C HNCO, HN(CO)CACB, HNCACB, HN(CA)CO] recorded for NGH1x, a truncated version of H1x containing the N-terminal and globular domains, but lacking the C-terminal domain. Experiments were conducted on double-labelled (15â¯N and 13C) NGH1x in 'low' and 'high salt,' to investigate the secondary structure content of the N-terminal domain of H1x under these conditions. We provide modelled structures of NGH1x (in low and high salt) based on the assigned chemical shifts in PDB format. The high salt structure of NGH1x (globular domain of H1x [GH1x; PDB: 2LSO] with the H1x NTD) was docked to the nucleosome to generate NGH1x- and GH1x-chromatosomes. The GH1x-chromatosome was generated for comparative purposes to elucidate the role of the N-terminal domain. We present raw data trajectories of molecular dynamics simulations of these chromatosomes in this article. The MD dataset provides nanosecond resolution data on the dynamics of GH1x- vs NGH1x-chromatosomes, which is useful to elucidate the DNA binding properties of the N-terminal domain of H1x in chromatin, as well as the dynamic behaviour of linker DNA in these chromatosomes.
RESUMO
Human linker histone H1 plays a seminal role in eukaryotic DNA packaging. H1 has a tripartite structure consisting of a central, conserved globular domain, which adopts a winged-helix fold, flanked by two variable N- and C-terminal domains. Here we present the backbone resonance assignments of the N-terminal domain and globular domain of human linker histone H1x in the presence and absence of the secondary structure stabilizer sodium perchlorate. Analysis of chemical shift changes between the two conditions is consistent with induction of transient secondary structural elements in the N-terminal domain of H1x in high ionic strength, which suggests that the N-terminal domain adopts significant alpha-helical conformations in the presence of DNA.