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|3nqu, resolution 2.50Å ()|
|Gene:||CENPA (Homo sapiens), HIST1H4A, H4/A, H4FA (Homo sapiens)|
Crystal structure of partially trypsinized (CENP-A/H4)2 heterotetramer
Centromeres are specified epigenetically, and the histone H3 variant CENP-A is assembled into the chromatin of all active centromeres. Divergence from H3 raises the possibility that CENP-A generates unique chromatin features to mark physically centromere location. Here we report the crystal structure of a subnucleosomal heterotetramer, human (CENP-A-H4)(2), that reveals three distinguishing properties encoded by the residues that comprise the CENP-A targeting domain (CATD; ref. 2): (1) a CENP-A-CENP-A interface that is substantially rotated relative to the H3-H3 interface; (2) a protruding loop L1 of the opposite charge as that on H3; and (3) strong hydrophobic contacts that rigidify the CENP-A-H4 interface. Residues involved in the CENP-A-CENP-A rotation are required for efficient incorporation into centromeric chromatin, indicating specificity for an unconventional nucleosome shape. DNA topological analysis indicates that CENP-A-containing nucleosomes are octameric with conventional left-handed DNA wrapping, in contrast to other recent proposals. Our results indicate that CENP-A marks centromere location by restructuring the nucleosome from within its folded histone core.
The structure of (CENP-A-H4)(2) reveals physical features that mark centromeres., Sekulic N, Bassett EA, Rogers DJ, Black BE, Nature. 2010 Aug 25. PMID:20739937
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.