2I46

Crystal structure of human TPP1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.213 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

The POT1-TPP1 telomere complex is a telomerase processivity factor.

Wang, F.Podell, E.R.Zaug, A.J.Yang, Y.Baciu, P.Cech, T.R.Lei, M.

(2007) Nature 445: 506-510

  • DOI: 10.1038/nature05454

  • PubMed Abstract: 
  • Telomeres were originally defined as chromosome caps that prevent the natural ends of linear chromosomes from undergoing deleterious degradation and fusion events. POT1 (protection of telomeres) protein binds the single-stranded G-rich DNA overhangs ...

    Telomeres were originally defined as chromosome caps that prevent the natural ends of linear chromosomes from undergoing deleterious degradation and fusion events. POT1 (protection of telomeres) protein binds the single-stranded G-rich DNA overhangs at human chromosome ends and suppresses unwanted DNA repair activities. TPP1 is a previously identified binding partner of POT1 that has been proposed to form part of a six-protein shelterin complex at telomeres. Here, the crystal structure of a domain of human TPP1 reveals an oligonucleotide/oligosaccharide-binding fold that is structurally similar to the beta-subunit of the telomere end-binding protein of a ciliated protozoan, suggesting that TPP1 is the missing beta-subunit of human POT1 protein. Telomeric DNA end-binding proteins have generally been found to inhibit rather than stimulate the action of the chromosome end-replicating enzyme, telomerase. In contrast, we find that TPP1 and POT1 form a complex with telomeric DNA that increases the activity and processivity of the human telomerase core enzyme. We propose that POT1-TPP1 switches from inhibiting telomerase access to the telomere, as a component of shelterin, to serving as a processivity factor for telomerase during telomere extension.


    Organizational Affiliation

    Department of Biological Chemistry, University of Michigan Medical School, MSRBIII 5301D, 1150 W. Medical Center Drive, Ann Arbor, Michigan 48109, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Adrenocortical dysplasia protein homolog
A, B
161Homo sapiensMutation(s): 0 
Gene Names: ACD (PIP1, PTOP, TINT1, TPP1)
Find proteins for Q96AP0 (Homo sapiens)
Go to Gene View: ACD
Go to UniProtKB:  Q96AP0
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.7 Å
  • R-Value Free: 0.251 
  • R-Value Work: 0.213 
  • Space Group: I 41 2 2
Unit Cell:
Length (Å)Angle (°)
a = 117.246α = 90.00
b = 117.246β = 90.00
c = 171.585γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
HKL-2000data scaling
CNSrefinement
SHARPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-11-28
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance