NMR assignments of human linker histone H1x N-terminal domain and globular domain in the presence and absence of perchlorate

Eukaryotic linker or H1 histones modulate DNA compaction and gene expression in vivo. In mammals, these proteins exist as multiple isotypes with distinct properties, suggesting a functional significance to the heterogeneity. Linker histones typically have a tripartite structure composed of a conserved central globular domain flanked by a highly variable short N-terminal domain and a longer highly basic C-terminal domain. We hypothesized that the variable terminal domains of individual subtypes contribute to their functional heterogeneity by influencing chromatin binding interactions. We developed a novel dual color fluorescence recovery after photobleaching assay system in which two H1 proteins fused to spectrally separable fluorescent proteins can be co-expressed and their independent binding kinetics simultaneously monitored in a single cell. This approach was combined with domain swap and point mutagenesis to determine the roles of the terminal domains in the differential binding characteristics of the linker histone isotypes, mouse H10 and H1c. Exchanging the N-terminal domains between H10 and H1c changed their overall binding affinity to that of the other variant. In contrast, switching the C-terminal domains altered the chromatin interaction surface of the globular domain. These results indicate that linker histone subtypes bind to chromatin in an intrinsically specific manner and that the highly variable terminal domains contribute to differences between subtypes. The methods developed in this study will have broad applications in studying dynamic properties of additional histone subtypes and other mobile proteins.

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Regulation of Cellular Dynamics and Chromosomal Binding Site Preference of Linker Histones H1.0 and H1.X

Molecular and Cellular Biology ◽

10.1128/mcb.00200-16 ◽

2016 ◽

Vol 36 (21) ◽

pp. 2681-2696 ◽

Cited By ~ 8

Author(s):

Mitsuru Okuwaki ◽

Mayumi Abe ◽

Miharu Hisaoka ◽

Kyosuke Nagata

Keyword(s):

Binding Site ◽

Dynamic Behavior ◽

Histone Variants ◽

Linker Histone ◽

Site Preference ◽

Globular Domain ◽

Linker Histones ◽

Terminal Domain ◽

Site Preferences ◽

Linker Histone Variants

Linker histones play important roles in the genomic organization of mammalian cells. Of the linker histone variants, H1.X shows the most dynamic behavior in the nucleus. Recent research has suggested that the linker histone variants H1.X and H1.0 have different chromosomal binding site preferences. However, it remains unclear how the dynamics and binding site preferences of linker histones are determined. Here, we biochemically demonstrated that the DNA/nucleosome and histone chaperone binding activities of H1.X are significantly lower than those of other linker histones. This explains why H1.X moves more rapidly than other linker histonesin vivo. Domain swapping between H1.0 and H1.X suggests that the globular domain (GD) and C-terminal domain (CTD) of H1.X independently contribute to the dynamic behavior of H1.X. Our results also suggest that the N-terminal domain (NTD), GD, and CTD cooperatively determine the preferential binding sites, and the contribution of each domain for this determination is different depending on the target genes. We also found that linker histones accumulate in the nucleoli when the nucleosome binding activities of the GDs are weak. Our results contribute to understanding the molecular mechanisms of dynamic behaviors, binding site selection, and localization of linker histones.

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Extended and dynamic linker histone-DNA interactions control chromatosome compaction

10.1101/2020.10.10.334474 ◽

2020 ◽

Author(s):

Sergei Rudnizky ◽

Hadeel Khamis ◽

Yuval Ginosar ◽

Efrat Goren ◽

Philippa Melamed ◽

...

Keyword(s):

Optical Tweezers ◽

Single Molecule ◽

Complex Dynamics ◽

Linker Histone ◽

Globular Domain ◽

Entry And Exit ◽

Nucleosome Core ◽

Terminal Domain ◽

Potential Regulatory Role ◽

Rapid Binding

AbstractChromatosomes play a fundamental role in chromatin regulation, but a detailed understanding of their structure is lacking, partially due to their complex dynamics. Using single-molecule DNA unzipping with optical tweezers, we reveal that linker histone interactions with DNA are remarkably extended, with the C-terminal domain binding both DNA linkers as far as ~ ±140 bp from the dyad. In addition to a symmetrical compaction of the nucleosome core governed by globular domain contacts at the dyad, the C-terminal domain compacts the nucleosome’s entry and exit. These interactions are dynamic, exhibiting rapid binding and dissociation, sensitive to phosphorylation of a specific residue, and crucial to determining the symmetry of the chromatosome’s core. Extensive unzipping of the linker DNA, which mimics its invasion by motor proteins, shifts H1 into an asymmetric, off-dyad configuration and triggers nucleosome decompaction, highlighting the plasticity of the chromatosome structure and its potential regulatory role.

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Backbone NMR assignments of the C-terminal domain of the human prion protein and its disease‐associated T183A variant

Biomolecular NMR Assignments ◽

10.1007/s12104-021-10005-y ◽

2021 ◽

Vol 15 (1) ◽

pp. 193-196

Author(s):

Máximo Sanz-Hernández ◽

Alfonso De Simone

Keyword(s):

Prion Protein ◽

Nmr Assignments ◽

Chemical Shifts ◽

Prion Diseases ◽

Random Coil ◽

Transmissible Spongiform Encephalopathies ◽

Globular Domain ◽

Structural Elements ◽

Spongiform Encephalopathies ◽

Human Prion Protein

AbstractTransmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders associated with the misfolding and aggregation of the human prion protein (huPrP). Despite efforts into investigating the process of huPrP aggregation, the mechanisms triggering its misfolding remain elusive. A number of TSE-associated mutations of huPrP have been identified, but their role at the onset and progression of prion diseases is unclear. Here we report the NMR assignments of the C-terminal globular domain of the wild type huPrP and the pathological mutant T183A. The differences in chemical shifts between the two variants reveal conformational alterations in some structural elements of the mutant, whereas the analyses of secondary shifts and random coil index provide indications on the putative mechanisms of misfolding of T183A huPrP.

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