5JH0

Crystal structure of the mitochondrial DNA packaging protein Abf2p in complex with DNA at 2.18 Angstrom resolution


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.18 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.211 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

DNA structure directs positioning of the mitochondrial genome packaging protein Abf2p.

Chakraborty, A.Lyonnais, S.Battistini, F.Hospital, A.Medici, G.Prohens, R.Orozco, M.Vilardell, J.Sola, M.

(2017) Nucleic Acids Res 45: 951-967

  • DOI: 10.1093/nar/gkw1147
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The mitochondrial genome (mtDNA) is assembled into nucleo-protein structures termed nucleoids and maintained differently compared to nuclear DNA, the involved molecular basis remaining poorly understood. In yeast (Saccharomyces cerevisiae), mtDNA is ...

    The mitochondrial genome (mtDNA) is assembled into nucleo-protein structures termed nucleoids and maintained differently compared to nuclear DNA, the involved molecular basis remaining poorly understood. In yeast (Saccharomyces cerevisiae), mtDNA is a ∼80 kbp linear molecule and Abf2p, a double HMG-box protein, packages and maintains it. The protein binds DNA in a non-sequence-specific manner, but displays a distinct 'phased-binding' at specific DNA sequences containing poly-adenine tracts (A-tracts). We present here two crystal structures of Abf2p in complex with mtDNA-derived fragments bearing A-tracts. Each HMG-box of Abf2p induces a 90° bend in the contacted DNA, causing an overall U-turn. Together with previous data, this suggests that U-turn formation is the universal mechanism underlying mtDNA compaction induced by HMG-box proteins. Combining this structural information with mutational, biophysical and computational analyses, we reveal a unique DNA binding mechanism for Abf2p where a characteristic N-terminal flag and helix are crucial for mtDNA maintenance. Additionally, we provide the molecular basis for A-tract mediated exclusion of Abf2p binding. Due to high prevalence of A-tracts in yeast mtDNA, this has critical relevance for nucleoid architecture. Therefore, an unprecedented A-tract mediated protein positioning mechanism regulates DNA packaging proteins in the mitochondria, and in combination with DNA-bending and U-turn formation, governs mtDNA compaction.


    Organizational Affiliation

    Structural MitoLab, Department of Structural Biology, "Maria de Maeztu" Unit of Excellence, Molecular Biology Institute Barcelona (IBMB-CSIC), Barcelona 08028, Spain maria.sola@ibmb.csic.es.



Macromolecules

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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
ARS-binding factor 2, mitochondrialA, D163Saccharomyces cerevisiae S288CMutation(s): 0 
Gene Names: ABF2HIM1YMR072WYM9916.11
Find proteins for Q02486 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Explore Q02486 
Go to UniProtKB:  Q02486
Protein Feature View
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  • Reference Sequence

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Entity ID: 3
MoleculeChainsLengthOrganism
DNA (5'-D(*TP*TP*AP*TP*AP*TP*TP*AP*TP*AP*TP*AP*AP*TP*TP*TP*AP*TP*TP*AP*TP*T)-3')C, F22Saccharomyces cerevisiae

Find similar nucleic acids by: Sequence  |  Structure

Entity ID: 2
MoleculeChainsLengthOrganism
DNA (5'-D(*AP*AP*TP*AP*AP*TP*AP*AP*AP*TP*TP*AP*TP*AP*TP*AP*AP*TP*AP*TP*AP*A)-3')B, E22Saccharomyces cerevisiae
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.18 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.209 
  • R-Value Observed: 0.211 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 88.49α = 90
b = 113.41β = 103.8
c = 67.71γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
XDSdata scaling
PHENIXphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Spanish Ministry of Economy and CompetitivenessSpainBFU2015-70645-R

Revision History 

  • Version 1.0: 2017-02-08
    Type: Initial release
  • Version 1.1: 2017-09-13
    Changes: Author supporting evidence