3mgr
Binding of Rubidium ions to the Nucleosome Core Particle
Structural highlights
FunctionH32_XENLA Core component of nucleosome. Nucleosomes wrap and compact DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called histone code, and nucleosome remodeling. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedHeavy metals have the potential to engage in strong bonding interactions and can thus function in essential as well as toxic or therapeutic capacities. We conducted crystallographic analyses of heavy cation binding to the nucleosome core particle and found that Co(2+) and Ni(2+) preferentially associate with the DNA major groove, in a sequence- and conformation-dependent manner. Conversely, Rb(+) and Cs(+) are found to bind only opportunistically to minor groove elements of the DNA, in particular at narrow AT dinucleotide sites. Furthermore, relative to Mn(2+) the aggressive coordination of Co(2+) and Ni(2+) to guanine bases is observed to induce a shift in histone-DNA register around the nucleosome center by stabilizing DNA stretching over one region accompanied by expulsion of two bases at an opposing location. These 'softer' transition metals also associate with multiple histone protein sites, including inter-nucleosomal cross-linking, and display a proclivity for coordination to histidine. Sustained binding and the ability to induce structural perturbations at specific locations in the nucleosome may contribute to genetic and epigenetic mechanisms of carcinogenesis mediated by Co(2+) and Ni(2+). Perturbations in nucleosome structure from heavy metal association.,Mohideen K, Muhammad R, Davey CA Nucleic Acids Res. 2010 May 21. PMID:20494975[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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