4IUP

crystal structure of Se-substituted arabidopsis thaliana SHH1 SAWADEE domain L200M/L218M mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.173 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history


Literature

Polymerase IV occupancy at RNA-directed DNA methylation sites requires SHH1.

Law, J.A.Du, J.Hale, C.J.Feng, S.Krajewski, K.Palanca, A.M.Strahl, B.D.Patel, D.J.Jacobsen, S.E.

(2013) Nature 498: 385-389

  • DOI: https://doi.org/10.1038/nature12178
  • Primary Citation of Related Structures:  
    4IUP, 4IUQ, 4IUR, 4IUT, 4IUU, 4IUV

  • PubMed Abstract: 

    DNA methylation is an epigenetic modification that has critical roles in gene silencing, development and genome integrity. In Arabidopsis, DNA methylation is established by DOMAINS REARRANGED METHYLTRANSFERASE 2 (DRM2) and targeted by 24-nucleotide small interfering RNAs (siRNAs) through a pathway termed RNA-directed DNA methylation (RdDM). This pathway requires two plant-specific RNA polymerases: Pol-IV, which functions to initiate siRNA biogenesis, and Pol-V, which functions to generate scaffold transcripts that recruit downstream RdDM factors. To understand the mechanisms controlling Pol-IV targeting we investigated the function of SAWADEE HOMEODOMAIN HOMOLOG 1 (SHH1), a Pol-IV-interacting protein. Here we show that SHH1 acts upstream in the RdDM pathway to enable siRNA production from a large subset of the most active RdDM targets, and that SHH1 is required for Pol-IV occupancy at these same loci. We also show that the SHH1 SAWADEE domain is a novel chromatin-binding module that adopts a unique tandem Tudor-like fold and functions as a dual lysine reader, probing for both unmethylated K4 and methylated K9 modifications on the histone 3 (H3) tail. Finally, we show that key residues within both lysine-binding pockets of SHH1 are required in vivo to maintain siRNA and DNA methylation levels as well as Pol-IV occupancy at RdDM targets, demonstrating a central role for methylated H3K9 binding in SHH1 function and providing the first insights into the mechanism of Pol-IV targeting. Given the parallels between methylation systems in plants and mammals, a further understanding of this early targeting step may aid our ability to control the expression of endogenous and newly introduced genes, which has broad implications for agriculture and gene therapy.


  • Organizational Affiliation

    Department of Molecular, Cell and Developmental Biology, University of California at Los Angeles, Los Angeles, California 90095, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SAWADEE HOMEODOMAIN HOMOLOG 1
A, B
135Arabidopsis thalianaMutation(s): 2 
Gene Names: F9L1.16At1g15215
UniProt
Find proteins for Q9XI47 (Arabidopsis thaliana)
Explore Q9XI47 
Go to UniProtKB:  Q9XI47
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9XI47
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.172 
  • R-Value Observed: 0.173 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.293α = 90
b = 56.733β = 93.36
c = 59.299γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PHENIXmodel building
PHENIXrefinement
HKL-2000data reduction
HKL-2000data scaling
PHENIXphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-05-01
    Type: Initial release
  • Version 1.1: 2013-05-15
    Changes: Database references
  • Version 1.2: 2013-07-10
    Changes: Database references