9QAX | pdb_00009qax

The catalytic core with C2 symmetry of human telomerase dimer

• PDB DOI: https://doi.org/10.2210/pdb9QAX/pdb
• EM Map EMD-52978: EMDB EMDataResource
• NAKB: 9QAX

• Classification: RNA BINDING PROTEIN
• Organism(s): Homo sapiens
• Expression System: Homo sapiens, Spodoptera
• Mutation(s): No 


• Deposited: 2025-02-28 Released: 2025-07-16 
• Deposition Author(s): Balch, S., Sekne, Z., Franco-Echevarria, E., Ludzia, P., Kretsch, R.C., Sun, W., Yu, H., Ghanim, G.E., Sigurdur, T.R., Ding, Y., Das, R., Nguyen, T.H.D.
• Funding Organization(s): UK Research and Innovation (UKRI), Jane Coffin Childs (JCC) Fund, European Molecular Biology Organization (EMBO), Wellcome Trust, National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS), Howard Hughes Medical Institute (HHMI), Chinese Scholarship Council, Biotechnology and Biological Sciences Research Council (BBSRC)

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Experimental Data Snapshot

• Method: ELECTRON MICROSCOPY
• Resolution: 3.30 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

Starting Model: experimental

Literature

Cryo-EM structure of human telomerase dimer reveals H/ACA RNP-mediated dimerization.

Balch, S., Sekne, Z., Franco-Echevarria, E., Ludzia, P., Kretsch, R.C., Sun, W., Yu, H., Ghanim, G.E., Thorkelsson, S., Ding, Y., Das, R., Nguyen, T.H.D.

(2025) Science 389: eadr5817-eadr5817

• PubMed: 40638752 
• DOI: https://doi.org/10.1126/science.adr5817
• Primary Citation of Related Structures:  
  9QAX, 9QAY, 9QAZ, 9QB2, 9QB3


• PubMed Abstract: 
  

  Telomerase ribonucleoprotein (RNP) synthesizes telomeric repeats at chromosome ends using a telomerase reverse transcriptase (TERT) and a telomerase RNA (hTR in humans). Previous structural work showed that human telomerase is typically monomeric, containing a single copy of TERT and hTR. Evidence for dimeric complexes exists, although the composition, high-resolution structure, and function remain elusive. Here, we report the cryo-electron microscopy (cryo-EM) structure of a human telomerase dimer bound to telomeric DNA. The structure reveals a 26-subunit assembly and a dimerization interface mediated by the Hinge and ACA box (H/ACA) RNP of telomerase. Premature aging disease mutations map to this interface. Disrupting dimer formation affects RNP assembly, bulk telomerase activity, and telomere maintenance in cells. Our findings address a long-standing enigma surrounding the telomerase dimer and suggest a role for the dimer in telomerase assembly.

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Organizational Affiliation: 
• MRC Laboratory of Molecular Biology, Cambridge, UK.
Biophysics Program, Stanford University, Stanford, CA, USA.
Key Laboratory of Molecular Epigenetics of the Ministry of Education, Northeast Normal University, Changchun, China.
Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, UK.
Department of Biochemistry, Stanford University, Stanford, CA, USA.
Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.

Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 4-mer - A1B1C1D1 Pseudo Symmetry: Asymmetric - C1 
Pseudo Stoichiometry: Hetero 4-mer - A2B1C1 

Biological assembly 1 assigned by authors and generated by (software)

Biological Assembly Evidence: electron microscopy

Macromolecule Content 

• Total Structure Weight: 378.06 kDa 
• Atom Count: 15,471 
• Modeled Residue Count: 1,507 
• Deposited Residue Count: 2,544 
• Unique protein chains: 4
• Unique nucleic acid chains: 2

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Telomerase reverse transcriptase	A	1,332	Homo sapiens	Mutation(s): 0  EC: 2.7.7.49
UniProt & NIH Common Fund Data Resources
Find proteins for O14746 (Homo sapiens) Explore O14746  Go to UniProtKB:  O14746
PHAROS:  O14746 GTEx:  ENSG00000164362

Entity ID: 3
Molecule	Chains	Sequence Length	Organism	Details	Image
Histone H2A	C [auth L]	130	Homo sapiens	Mutation(s): 0
UniProt
Find proteins for B2R5B3 (Homo sapiens) Explore B2R5B3  Go to UniProtKB:  B2R5B3

Entity ID: 4
Molecule	Chains	Sequence Length	Organism	Details	Image
Histone H2B	D [auth M]	166	Homo sapiens	Mutation(s): 0
UniProt
Find proteins for B4DR52 (Homo sapiens) Explore B4DR52  Go to UniProtKB:  B4DR52

Entity ID: 6
Molecule	Chains	Sequence Length	Organism	Details	Image
Adrenocortical dysplasia protein homolog	F [auth O]	458	Homo sapiens	Mutation(s): 0  Gene Names: ACD, PIP1, PTOP, TINT1, TPP1
UniProt & NIH Common Fund Data Resources
Find proteins for Q96AP0 (Homo sapiens) Explore Q96AP0  Go to UniProtKB:  Q96AP0
PHAROS:  Q96AP0 GTEx:  ENSG00000102977

Entity ID: 2
Molecule	Chains	Length	Organism	Image
hTR, human telomerase RNA	B	451	Homo sapiens

Entity ID: 5
Molecule	Chains	Length	Organism	Image
DNA (5'-D(P*GP*TP*TP*AP*GP*GP*G)-3')	E [auth N]	7	Homo sapiens

Experimental Data & Validation

Experimental Data

• Method: ELECTRON MICROSCOPY
• Resolution: 3.30 Å
• Aggregation State: PARTICLE 
• Reconstruction Method: SINGLE PARTICLE 

EM Software:

Task	Software Package	Version
RECONSTRUCTION	RELION	5.0
MODEL REFINEMENT	REFMAC	5.8
MODEL REFINEMENT	Servalcat	0.4.70

Structure Validation

Entry History & Funding Information

Deposition Data

• Released Date: 2025-07-16 
Deposition Author(s): Balch, S., Sekne, Z., Franco-Echevarria, E., Ludzia, P., Kretsch, R.C., Sun, W., Yu, H., Ghanim, G.E., Sigurdur, T.R., Ding, Y., Das, R., Nguyen, T.H.D.

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Funding Organization	Location	Grant Number
UK Research and Innovation (UKRI)	United Kingdom	MC_UP_1201/19
Jane Coffin Childs (JCC) Fund	United States	--
European Molecular Biology Organization (EMBO)	European Union	--
Wellcome Trust	United Kingdom	226015/Z/22/Z
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	2R35GM122579
Howard Hughes Medical Institute (HHMI)	United States	--
Chinese Scholarship Council	China	202206620047
Biotechnology and Biological Sciences Research Council (BBSRC)	United Kingdom	BB/X01102X/1

Revision History  

• Version 1.0: 2025-07-16
  Type: Initial release
  
• Version 1.1: 2025-07-23
  Changes: Data collection, Database references