9HCL: Human TRF1 TRFH domain

Crystal structure of human TRF1 TRFH domain in complex with compound 12. Determined by X-ray diffraction at 1.87 Å resolution. Released 19 Nov 2025.

Method: X-ray diffraction
Resolution: 1.87 Å
Organism: Homo sapiens
Chains: 1
Atoms: 1,844
Mol. weight: 26.58 kDa
Ligands: TWC
Released: 19 Nov 2025

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

Secondary structure: helices and β-sheets

9HCL contains 11 α-helices and 0 β-strands across 1 chain. 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: 11 helices, 0 β-strands

Element	Residues	Length
α-helix	64-92	29
α-helix	95-109	15
α-helix	117-133	17
α-helix	141-146	6
α-helix	150-158	9
α-helix	166-186	21
α-helix	190-200	11
α-helix	209-219	11
α-helix	227-230	4
α-helix	233-251	19
α-helix	255-266	12

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Telomeric repeat-binding factor 1	A	protein	224	Homo sapiens	P54274 (AlphaFold model)

Sequence of entity 1 (A), FASTA

>9HCL_1 Telomeric repeat-binding factor 1 (chains A)
SNAQVQVGAPEEEEEEEEDAGLVAEAEAVAAGWMLDFLCLSLCRAFRDGRSEDFRRTRNS
AEAIIHGLSSLTACQLRTIYICQFLTRIAAGKTLDAQFENDERITPLESALMIWGSIEKE
HDKLHEEIQNLIKIQAIAVCMENGNFKEAEEVFERIFGDPNSHMPFKSKLLMIISQKDTF
HSFFQHFSYNHMMEKIKSYVNYVLSEKSSTFLMKAAAKVVESKR

Ligands and cofactors

ID	Name	Formula	Copies
TWC	2-ethyl-5-(trifluoromethyl)-2,4-dihydro-3H-pyrazol-3-one	C6 H7 F3 N2 O	3

Water and common crystallization additives (DMS, GOL) are not listed.

Primary citation

Discovery of first-in-class inhibitors of the TRF1:TIN2 protein:protein interaction by fragment screening. Casale, G., Liu, M., Le Bihan, Y.V. et al. Sci Rep (2025) 15:40922-40922. DOI 10.1038/s41598-025-23858-3 · PubMed

Other PDB entries of the same protein (UniProt P54274 (AlphaFold model), which also has an AlphaFold model), best resolution first:

9HCZ 1.55 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 6
9HCX 1.69 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 53
9HCP 1.7 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 15
9HCT 1.7 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 50
9HD1 1.73 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 59
9HD9 1.87 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 1
9HF9 1.9 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 5
9HCN 1.93 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 46
9HCY 1.93 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 54
9HD0 1.93 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 55
9HCR 1.93 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 48
9HCQ 1.96 Å, Crystal structure of human TRF1 TRFH domain in complex with compound 47

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