1MJO

METHIONINE HOLOREPRESSOR MUTANT (Q44K) PLUS COREPRESSOR (S-ADENOSYL METHIONINE) COMPLEXED TO THE MINIMAL MET CONSENSUS OPERATOR WITH THE CENTRAL TA STEP MUTATED TO AT


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

Direct and indirect readout in mutant Met repressor-operator complexes.

Garvie, C.W.Phillips, S.E.

(2000) Structure 8: 905-914

  • DOI: https://doi.org/10.1016/s0969-2126(00)00182-9
  • Primary Citation of Related Structures:  
    1MJ2, 1MJM, 1MJO, 1MJP, 1MJQ

  • PubMed Abstract: 

    The methionine repressor, MetJ, represses the transcription of genes involved in methionine biosynthesis by binding to arrays of two to five adjacent copies of an eight base-pair 'metbox' sequence. Naturally occurring operators differ from the consensus sequence to a greater extent as the number of metboxes increases. MetJ, while accommodating this sequence variation in natural operators, is very sensitive to particular base changes, even where bases are not directly contacted in the crystal structure of a complex formed between the repressor and consensus operator. Here we report the high-resolution structure of a MetJ mutant, Q44K, bound to the consensus operator sequence (Q44Kwt19) and two related sequences containing mutations at sites believed to be important for indirect readout at non-contacted bases. The overall structure of the Q44Kwt19 complex is very similar to the wild-type complex, but there are small variations in sugar-phosphate backbone conformation and direct contacts to the DNA bases. The mutant complexes show a mixture of direct and indirect readout of sequence variations, with differences in direct contacts and DNA conformation. Comparison of the wild-type and mutant repressor-operator complexes shows that the repressor makes sufficiently strong interactions with the sugar-phosphate backbone to accommodate some variation in operator sequence with minor changes in direct bases contacts. The reduction in repressor affinity for the two mutant repressor complexes can be partially attributed to a loss in direct contacts to the DNA. In one case, however, the replacement of a flexible TA base-step leads to an unfavourable DNA conformation that reduces the stability of the repressor-operator complex.


  • Organizational Affiliation

    Astbury Centre for Structural Molecular Biology, School of Biochemistry and Molecular Biology, University of Leeds, LS2 9JT, Leeds, UK.


Macromolecules

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
METHIONINE REPRESSORC [auth A],
D [auth B],
E [auth C],
F [auth D]
104Escherichia coliMutation(s): 1 
Gene Names: METJ
UniProt
Find proteins for P0A8U6 (Escherichia coli (strain K12))
Explore P0A8U6 
Go to UniProtKB:  P0A8U6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A8U6
Sequence Annotations
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  • Reference Sequence

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Entity ID: 1
MoleculeChains LengthOrganismImage
CONSENSUS DNA OPERATOR DUPLEX WITH THE CENTRAL TA STEP MUTATED TO ATA [auth F],
B [auth G]
19N/A
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.241 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.189 
  • Space Group: P 32 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 117.505α = 90
b = 117.505β = 90
c = 90.208γ = 120
Software Package:
Software NamePurpose
AMoREphasing
X-PLORrefinement
MOSFLMdata reduction
CCP4data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-08-02
    Type: Initial release
  • Version 1.1: 2008-05-22
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Database references, Derived calculations
  • Version 1.4: 2023-08-02
    Changes: Refinement description