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9gxa

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CENP-A/H4 di-tetrasome assembled on alpha-satellite DNA.

Structural highlights

9gxa is a 10 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	Electron Microscopy, Resolution 4.01Å
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

CENPA_HUMAN Histone H3-like variant which exclusively replaces conventional H3 in the nucleosome core of centromeric chromatin at the inner plate of the kinetochore. Required for recruitment and assembly of kinetochore proteins, mitotic progression and chromosome segregation. May serve as an epigenetic mark that propagates centromere identity through replication and cell division. The CENPA-H4 heterotetramer can bind DNA by itself (in vitro).^[1] ^[2]

Publication Abstract from PubMed

The centromere is a part of the chromosome that is essential for the even segregation of duplicated chromosomes during cell division. It is epigenetically defined by the presence of the histone H3 variant CENP-A. CENP-A associates specifically with a group of 16 proteins that form the centromere-associated network of proteins (CCAN). In mitosis, the kinetochore forms on the CCAN to connect the duplicated chromosomes to the microtubules protruding from the cell poles. Previous studies have shown that CENP-A replaces H3 in nucleosomes, and recently the structures of CENP-A-containing nucleosomes in complex with CCANs have been revealed, but they show only a limited interaction between CCANs and CENP-A. Here, we report the cryoEM structure of 2x(CENP-A/H4)(2)-di-tetramers assembled on DNA in the absence of H2A/H2B histone dimer and speculate how (CENP-A/H4)(2)-tetramers and -di-tetramers might serve as a platform for CCAN organization.

Non-nucleosomal (CENP-A/H4)(2) - DNA complexes as a possible platform for centromere organization.,Ali-Ahmad A, Mors M, Carrer M, Li X, Bilokapic S, Halic M, Cascella M, Sekulic N bioRxiv [Preprint]. 2025 Jan 1:2024.12.31.630874. doi: 10.1101/2024.12.31.630874. PMID:39803555^[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Sekulic N, Bassett EA, Rogers DJ, Black BE. The structure of (CENP-A-H4)(2) reveals physical features that mark centromeres. Nature. 2010 Aug 25. PMID:20739937 doi:10.1038/nature09323
↑ Hu H, Liu Y, Wang M, Fang J, Huang H, Yang N, Li Y, Wang J, Yao X, Shi Y, Li G, Xu RM. Structure of a CENP-A-histone H4 heterodimer in complex with chaperone HJURP. Genes Dev. 2011 May 1;25(9):901-6. Epub 2011 Apr 8. PMID:21478274 doi:10.1101/gad.2045111
↑ Ali-Ahmad A, Mors M, Carrer M, Li X, Bilokapić S, Halić M, Cascella M, Sekulić N. Non-nucleosomal (CENP-A/H4)(2) centromere organization. bioRxiv [Preprint]. 2025 Jan 1:2024.12.31.630874. PMID:39803555 doi:10.1101/2024.12.31.630874