3U50

Crystal Structure of the Tetrahymena telomerase processivity factor Teb1 OB-C


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.218 

wwPDB Validation   3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Structural basis for Tetrahymena telomerase processivity factor Teb1 binding to single-stranded telomeric-repeat DNA.

Zeng, Z.Min, B.Huang, J.Hong, K.Yang, Y.Collins, K.Lei, M.

(2011) Proc Natl Acad Sci U S A 108: 20357-20361

  • DOI: 10.1073/pnas.1113624108
  • Primary Citation of Related Structures:  
    3U50, 3U4Z, 3U4V, 3U58

  • PubMed Abstract: 
  • Telomerase copies its internal RNA template to synthesize telomeric DNA repeats. Unlike other polymerases, telomerase can retain its single-stranded product through multiple rounds of template dissociation and repositioning to accomplish repeat addition processivity (RAP) ...

    Telomerase copies its internal RNA template to synthesize telomeric DNA repeats. Unlike other polymerases, telomerase can retain its single-stranded product through multiple rounds of template dissociation and repositioning to accomplish repeat addition processivity (RAP). Tetrahymena telomerase holoenzyme RAP depends on a subunit, Teb1, with autonomous DNA-binding activity. Sequence homology and domain modeling suggest that Teb1 is a paralog of RPA70C, the largest subunit of the single-stranded DNA-binding factor replication protein (RPA), but unlike RPA, Teb1 binds DNA with high specificity for telomeric repeats. To understand the structural basis and significance of telomeric-repeat DNA recognition by Teb1, we solved crystal structures of three proposed Teb1 DNA-binding domains and defined amino acids of each domain that contribute to DNA interaction. Our studies indicate that two central Teb1 DNA-binding oligonucleotide/oligosaccharide-binding-fold domains, Teb1A and Teb1B, achieve high affinity and selectivity of telomeric-repeat recognition by principles similar to the telomere end-capping protein POT1 (protection of telomeres 1). An additional C-terminal Teb1 oligonucleotide/oligosaccharide-binding-fold domain, Teb1C, has features shared with the RPA70 C-terminal domain including a putative direct DNA-binding surface that is critical for high-RAP activity of reconstituted holoenzyme. The Teb1C zinc ribbon motif does not contribute to DNA binding but is nonetheless required for high-RAP activity, perhaps contributing to Teb1 physical association with the remainder of the holoenzyme. Our results suggest the biological model that high-affinity DNA binding by Teb1AB recruits holoenzyme to telomeres and subsequent Teb1C-DNA association traps product in a sliding-clamp-like manner that does not require high-affinity DNA binding for high stability of enzyme-product association.


    Organizational Affiliation

    Howard Hughes Medical Institute, Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Telomerase-associated protein 82A [auth C]172Tetrahymena thermophilaMutation(s): 0 
Gene Names: TAP82
Find proteins for D2CVN6 (Tetrahymena thermophila (strain SB210))
Explore D2CVN6 
Go to UniProtKB:  D2CVN6
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download Ideal Coordinates CCD File 
B [auth C]ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.50 Å
  • R-Value Free: 0.253 
  • R-Value Work: 0.214 
  • R-Value Observed: 0.218 
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 80.609α = 90
b = 80.609β = 90
c = 82.081γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-12-14
    Type: Initial release
  • Version 1.1: 2012-05-23
    Changes: Database references
  • Version 1.2: 2015-01-28
    Changes: Other
  • Version 1.3: 2017-11-08
    Changes: Refinement description