Biological Assembly 1  

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 37.87 kDa 
• Atom Count: 2,066 
• Modelled Residue Count: 191 
• Deposited Residue Count: 264 
• Unique protein chains: 1
• Unique nucleic acid chains: 2

 4J19

Structure of a novel telomere repeat binding protein bound to DNA

• PDB DOI: 10.2210/pdb4J19/pdb
• NDB: NA2249

• Classification: Transcription/DNA
• Organism(s): Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2013-02-01 Released: 2013-05-29 
• Deposition Author(s): Kappei, D., Butter, F., Benda, C., Scheibe, M., Draskovic, I., Stevense, M., Lopes Novo, C., Basquin, C., Krastev, D.B., Kittler, R., Jessberger, R., Londono-Vallejo, A.J., Mann, M., Buchholz, F.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.90 Å
• R-Value Free: 0.221 
• R-Value Work: 0.172 
• R-Value Observed: 0.174 

Literature

HOT1 is a mammalian direct telomere repeat-binding protein contributing to telomerase recruitment.

Kappei, D., Butter, F., Benda, C., Scheibe, M., Draskovic, I., Stevense, M., Novo, C.L., Basquin, C., Araki, M., Araki, K., Krastev, D.B., Kittler, R., Jessberger, R., Londono-Vallejo, J.A., Mann, M., Buchholz, F.

(2013) EMBO J 32: 1681-1701

• PubMed: 23685356 
• DOI: 10.1038/emboj.2013.105
• Primary Citation of Related Structures:  
  4J19


• PubMed Abstract: 
  

Telomeres are repetitive DNA structures that, together with the shelterin and the CST complex, protect the ends of chromosomes. Telomere shortening is mitigated in stem and cancer cells through the de novo addition of telomeric repeats by telomerase. Telomere elongation requires the delivery of the telomerase complex to telomeres through a not yet fully understood mechanism. Factors promoting telomerase-telomere interaction are expected to directly bind telomeres and physically interact with the telomerase complex. In search for such a factor we carried out a SILAC-based DNA-protein interaction screen and identified HMBOX1, hereafter referred to as homeobox telomere-binding protein 1 (HOT1). HOT1 directly and specifically binds double-stranded telomere repeats, with the in vivo association correlating with binding to actively processed telomeres. Depletion and overexpression experiments classify HOT1 as a positive regulator of telomere length. Furthermore, immunoprecipitation and cell fractionation analyses show that HOT1 associates with the active telomerase complex and promotes chromatin association of telomerase. Collectively, these findings suggest that HOT1 supports telomerase-dependent telomere elongation.

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Organizational Affiliation: 

Medical Systems Biology, Faculty of Medicine Carl Gustav Carus, University Cancer Center, Dresden University of Technology, 01307 Dresden, Germany.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Homeobox-containing protein 1	A, B	113	Homo sapiens	Mutation(s): 0  Gene Names: HMBOX1, HOT1, TAH1
UniProt & NIH Common Fund Data Resources
Find proteins for Q6NT76 (Homo sapiens) Explore Q6NT76  Go to UniProtKB:  Q6NT76
PHAROS:  Q6NT76

Entity ID: 2
Molecule	Chains	Length	Organism	Image
DNA (5'-D(*CP*TP*GP*TP*TP*AP*GP*GP*GP*TP*TP*AP*GP*GP*GP*TP*TP*AP*G)-3')	C	19	N/A

Entity ID: 3
Molecule	Chains	Length	Organism	Image
DNA (5'-D(*TP*CP*TP*AP*AP*CP*CP*CP*TP*AP*AP*CP*CP*CP*TP*AP*AP*CP*A)-3')	D	19	N/A

Small Molecules

Ligands 1 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
CL	E [auth C]	CHLORIDE ION Cl VEXZGXHMUGYJMC-UHFFFAOYSA-M

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.90 Å
• R-Value Free: 0.221 
• R-Value Work: 0.172 
• R-Value Observed: 0.174 
• Space Group: C 2 2 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 111.433	α = 90
b = 116.49	β = 90
c = 75.67	γ = 90

Software Package:

Software Name	Purpose
PHENIX	model building
PHENIX	refinement
XDS	data reduction
XDS	data scaling
PHENIX	phasing

Structure Validation

Entry History 

Deposition Data

• Released Date: 2013-05-29 
Deposition Author(s): Kappei, D., Butter, F., Benda, C., Scheibe, M., Draskovic, I., Stevense, M., Lopes Novo, C., Basquin, C., Krastev, D.B., Kittler, R., Jessberger, R., Londono-Vallejo, A.J., Mann, M., Buchholz, F.

Revision History  

• Version 1.0: 2013-05-29
  Type: Initial release
  
• Version 1.1: 2013-07-10
  Changes: Database references
• Version 1.2: 2017-11-15
  Changes: Refinement description