4IUQ

crystal structure of SHH1 SAWADEE domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.81 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.204 

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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: 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) ...

    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
MoleculeChainsSequence LengthOrganismDetailsImage
SAWADEE HOMEODOMAIN HOMOLOG 1B [auth A],
A [auth B]
135Arabidopsis thalianaMutation(s): 0 
Gene Names: F9L1.16At1g15215SHH1DTF1
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
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CVM
Query on CVM

Download Ideal Coordinates CCD File 
D [auth B],
F [auth A]
CYMAL-4
C22 H40 O11
JRNQXDHDSXBSFV-WXFJLFHKSA-N
 Ligand Interaction
ZN
Query on ZN

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

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.81 Å
  • R-Value Free: 0.261 
  • R-Value Work: 0.201 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.708α = 90
b = 117.691β = 90
c = 53.409γ = 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