9OSC: HP1gamma chromoshadow domain

Crystal structure of HP1gamma chromoshadow domain in complex with KAP1 peptide. Determined by X-ray diffraction at 1.77 Å resolution. Released 4 Feb 2026.

Method: X-ray diffraction
Resolution: 1.77 Å
Organism: Homo sapiens
Chains: 2
Atoms: 602
Mol. weight: 8.94 kDa
Released: 4 Feb 2026

Explore 9OSC in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

9OSC contains 4 α-helices and 5 β-strands across 2 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 4 helices, 4 β-strands

Element	Residues	Length	Sheet
α-helix	116-119	4
α-helix	121-122	2
β-strand	123-130	8	1
β-strand	137-142	6	1
β-strand	149-152	4	1
α-helix	153-159	7
α-helix	161-169	9
β-strand	172-173	2	2

Chain C: 0 helices, 1 β-strand

Element	Residues	Length	Sheet
β-strand	488-489	2	2

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Chromobox protein homolog 3	A	protein	67	Homo sapiens	Q13185 (AlphaFold model)
Transcription intermediary factor 1-beta	C	protein	11	Homo sapiens	Q13263 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9OSC_1 Chromobox protein homolog 3 (chains A)
AADKPRGFARGLDPERIIGATDSSGELMFLMKWKDSDEADLVLAKEANMKCPQIVIAFYE
ERLTWHS

Sequence of entity 2 (C), FASTA

>9OSC_2 Transcription intermediary factor 1-beta (chains C)
RKVPRVSLERL

Primary citation

HP1 gamma self-assembles and cooperates with KAP1 in repression of long noncoding RNA AI662270 in ESCs. Gaurav, N., Qin, W., Selvam, K. et al. Cell Rep (2026) 45:116874-116874. DOI 10.1016/j.celrep.2025.116874 · PubMed

Other PDB entries of the same protein (UniProt Q13185 (AlphaFold model), which also has an AlphaFold model), best resolution first:

5T1I 1.6 Å, CBX3 chromo shadow domain in complex with histone H3 peptide
3KUP 1.77 Å, Crystal Structure of the CBX3 Chromo Shadow Domain
8JZW 1.8 Å, Cystal structure of HP1 in complex with TRIM66 peptide
3TZD 1.81 Å, Crystal structure of the complex of Human Chromobox Homolog 3 (CBX3)
6HW2 1.94 Å, The Crystal Structure of CaV beta4c in complex with HP1gamma chromo shadow domains
3DM1 2.4 Å, Crystal structure of the complex of human chromobox homolog 3 (CBX3) with peptide
2L11 Solution NMR structure of the Cbx3 in complex with H3K9me3 peptide

Browse structure collections

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