6MHT

TERNARY STRUCTURE OF HHAI METHYLTRANSFERASE WITH ADOHCY AND DNA CONTAINING 4'-THIO-2'DEOXYCYTIDINE AT THE TARGET

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.186 

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This is version 2.0 of the entry. See complete history. 


Literature

DNA containing 4'-thio-2'-deoxycytidine inhibits methylation by HhaI methyltransferase.

Kumar, S., Horton, J.R., Jones, G.D., Walker, R.T., Roberts, R.J., Cheng, X.

(1997) Nucleic Acids Res 25: 2773-2783

  • DOI: 10.1093/nar/25.14.2773
  • Primary Citation of Related Structures:  
    6MHT

  • PubMed Abstract: 

    • 4'-Thio-2'-deoxycytidine was synthesized as a 5'- protected phosphoramidite compatible with solid phase DNA synthesis. When incorporated as the target cytosine (C*) in the GC*GC recognition sequence for the DNA methyltransferase M. HhaI, methyl transfer was strongly inhibited ...

    4'-Thio-2'-deoxycytidine was synthesized as a 5'- protected phosphoramidite compatible with solid phase DNA synthesis. When incorporated as the target cytosine (C*) in the GC*GC recognition sequence for the DNA methyltransferase M. HhaI, methyl transfer was strongly inhibited. In contrast, these same oligonucleotides were normal substrates for the cognate restriction endonuclease R. HhaI and its isoschizomer R. Hin P1I. M. HhaI was able to bind both 4'-thio-modified DNA and unmodified DNA to equivalent extents under equilibrium conditions. However, the presence of 4'-thio-2'-deoxycytidine decreased the half-life of the complex by >10-fold. The crystal structure of a ternary complex of M. HhaI, AdoMet and DNA containing 4'-thio-2'-deoxycytidine was solved at 2.05 A resolution with a crystallographic R-factor of 0.186 and R-free of 0.231. The structure is not grossly different from previously solved ternary complexes containing M. HhaI, DNA and AdoHcy. The difference electron density suggests partial methylation at C5 of the flipped target 4'-thio-2'-deoxycytidine. The inhibitory effect of the 4'sulfur atom on enzymatic activity may be traced to perturbation of a step in the methylation reaction after DNA binding but prior to methyl transfer. This inhibitory effect can be partially overcome after a considerably long time in the crystal environment where the packing prevents complex dissociation and the target is accurately positioned within the active site.

    Organizational Affiliation: 

    New England Biolabs, 32 Tozer Road, Beverly, MA 01915, USA. kumar@neb.com



Macromolecules

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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
CYTOSINE-SPECIFIC METHYLTRANSFERASE HHAIC [auth A]327Haemophilus haemolyticusMutation(s): 0 
EC: 2.1.1.73 (PDB Primary Data), 2.1.1.37 (UniProt)
UniProt
Find proteins for P05102 (Haemophilus parahaemolyticus)
Explore P05102 
Go to UniProtKB:  P05102
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP05102
Protein Feature View
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  • Reference Sequence

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Entity ID: 1
MoleculeChainsLengthOrganismImage
DNA (5'-D(P*CP*CP*AP*TP*GP*(5CM)P*GP*CP*TP*GP*AP*C)-3')A [auth C]12Haemophilus haemolyticus
Protein Feature View
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  • Reference Sequence

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Entity ID: 2
MoleculeChainsLengthOrganismImage
DNA (5'-D(P*GP*TP*CP*AP*GP*(4SC)P*GP*CP*AP*TP*GP*G)-3')B [auth D]12N/A
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SAM
Query on SAM
Download Ideal Coordinates CCD File 
D S-ADENOSYLMETHIONINE
C15 H22 N6 O5 S
MEFKEPWMEQBLKI-FCKMPRQPSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.186 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 99.86α = 90
b = 99.86β = 90
c = 325.2γ = 120
Software Package:
Software NamePurpose
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

  • Deposited Date: 1998-08-05 
  • Released Date: 1998-08-12 
    • Deposition Author(s): Cheng, X.

Revision History  (Full details and data files)

  • Version 1.0: 1998-08-12
    Type: Initial release
  • Version 1.1: 2008-05-22
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 2.0: 2022-04-13
    Changes: Database references, Derived calculations, Non-polymer description, Structure summary