1FJX

STRUCTURE OF TERNARY COMPLEX OF HHAI METHYLTRANSFERASE MUTANT (T250G) IN COMPLEX WITH DNA AND ADOHCY

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.26 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.207 

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This is version 1.4 of the entry. See complete history. 


Literature

Functional roles of the conserved threonine 250 in the target recognition domain of HhaI DNA methyltransferase.

Vilkaitis, G., Dong, A., Weinhold, E., Cheng, X., Klimasauskas, S.

(2000) J Biol Chem 275: 38722-38730

  • DOI: 10.1074/jbc.m005278200
  • Primary Citation of Related Structures:  
    1FJX

  • PubMed Abstract: 

    • DNA cytosine-5-methyltransferase HhaI recognizes the GCGC sequence and flips the inner cytosine out of DNA helix and into the catalytic site for methylation. The 5'-phosphate of the flipped out cytosine is in contact with the conserved Thr-250 from the target recognition domain ...

    DNA cytosine-5-methyltransferase HhaI recognizes the GCGC sequence and flips the inner cytosine out of DNA helix and into the catalytic site for methylation. The 5'-phosphate of the flipped out cytosine is in contact with the conserved Thr-250 from the target recognition domain. We have produced 12 mutants of Thr-250 and examined their methylation potential in vivo. Six active mutants were subjected to detailed biochemical and structural studies. Mutants with similar or smaller side chains (Ser, Cys, and Gly) are very similar to wild-type enzyme in terms of steady-state kinetic parameters k(cat), K(m)(DNA), K(m)(AdoMet). In contrast, the mutants with bulkier side chains (Asn, Asp, and His) show increased K(m) values for both substrates. Fluorescence titrations and stopped-flow kinetic analysis of interactions with duplex oligonucleotides containing 2-aminopurine at the target base position indicate that the T250G mutation leads to a more polar but less solvent-accessible position of the flipped out target base. The x-ray structure of the ternary M. HhaI(T250G).DNA.AdoHcy complex shows that the target cytosine is locked in the catalytic center of enzyme. The space created by the mutation is filled by water molecules and the adjacent DNA backbone atoms dislocate slightly toward the missing side chain. In aggregate, our results suggest that the side chain of Thr-250 is involved in constraining the conformation the DNA backbone and the target base during its rotation into the catalytic site of enzyme.

    Organizational Affiliation: 

    Institute of Biotechnology, Laboratory of Biological DNA Modification, LT-2028 Vilnius, Lithuania.



Macromolecules

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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
HHAI DNA METHYLTRANSFERASEC [auth A]327Haemophilus haemolyticusMutation(s): 1 
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(*TP*GP*AP*TP*AP*GP*CP*GP*CP*TP*AP*TP*C)-3')A [auth C],
B [auth D]		13N/A
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SAH
Query on SAH
Download Ideal Coordinates CCD File 
F [auth A]S-ADENOSYL-L-HOMOCYSTEINE
C14 H20 N6 O5 S
ZJUKTBDSGOFHSH-WFMPWKQPSA-N		 Ligand Interaction
SO4
Query on SO4
Download Ideal Coordinates CCD File 
D [auth A],
E [auth A]		SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L		 Ligand Interaction
Binding Affinity Annotations 
IDSourceBinding Affinity
DNA PDBBind:  1FJX Kd: 1.4 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.26 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.207 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 98.46α = 90
b = 98.46β = 90
c = 323.22γ = 120
Software Package:
Software NamePurpose
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-12-15
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2018-01-31
    Changes: Experimental preparation
  • Version 1.4: 2018-03-14
    Changes: Database references