Crystal structure of the MSMEG_6754 dehydratase from Mycobacterium smegmatis

Experimental Data Snapshot

  • Resolution: 1.50 Å
  • R-Value Free: 0.178 
  • R-Value Work: 0.159 
  • R-Value Observed: 0.160 

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A New Dehydratase Conferring Innate Resistance to Thiacetazone and Intra-Amoebal Survival of Mycobacterium Smegmatis.

Carrere-Kremer, S.Blaise, M.Singh, V.K.Alibaud, L.Tuaillon, E.Halloum, I.Van De Weerd, R.Guerardel, Y.Drancourt, M.Takiff, H.Geurtsen, J.Kremer, L.

(2015) Mol Microbiol 96: 1085

  • DOI: https://doi.org/10.1111/mmi.12992
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Nontuberculous mycobacteria are innately resistant to most antibiotics, although the mechanisms responsible for their drug resistance remain poorly understood. They are particularly refractory to thiacetazone (TAC), a second-line antitubercular drug. Herein, we identified MSMEG_6754 as essential for the innate resistance of Mycobacterium smegmatis to TAC. Transposon-mediated and targeted disruption of MSMEG_6754 resulted in hypersusceptibility to TAC. Conversely, introduction of MSMEG_6754 into Mycobacterium tuberculosis increased resistance 100-fold. Resolution of the crystal structure of MSMEG_6754 revealed a homodimer in which each monomer comprises two hot-dog domains characteristic of dehydratase-like proteins and very similar to the HadAB complex involved in mycolic acid biosynthesis. Gene inactivation of the essential hadB dehydratase could be achieved in M. smegmatis and M. tuberculosis only when the strains carried an integrated copy of MSMEG_6754, supporting the idea that MSMEG_6754 and HadB share redundant dehydratase activity. Using M. smegmatis-Acanthamoeba co-cultures, we found that intra-amoebal growth of the MSMEG_6754 deleted strain was significantly reduced compared with the parental strain. This in vivo growth defect was fully restored upon complementation with catalytically active MSMEG_6754 or HadABC, indicating that MSMEG_6754 plays a critical role in the survival of M. smegmatis within the environmental host.

  • Organizational Affiliation

    Laboratoire de Dynamique des Interactions Membranaires Normales et Pathologiques, CNRS UMR 5235, Université de Montpellier, case 107, Place Eugène Bataillon, 34095 Montpellier Cedex 05, France.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
MAOC LIKE DOMAIN PROTEIN343Mycolicibacterium smegmatisMutation(s): 0 
Find proteins for A0R724 (Mycolicibacterium smegmatis (strain ATCC 700084 / mc(2)155))
Explore A0R724 
Go to UniProtKB:  A0R724
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0R724
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on POG

Download Ideal Coordinates CCD File 
B [auth A](20S)-2,5,8,11,14,17-HEXAMETHYL-3,6,9,12,15,18-HEXAOXAHENICOSANE-1,20-DIOL
C21 H44 O8
Query on BTB

Download Ideal Coordinates CCD File 
C8 H19 N O5
Experimental Data & Validation

Experimental Data

  • Resolution: 1.50 Å
  • R-Value Free: 0.178 
  • R-Value Work: 0.159 
  • R-Value Observed: 0.160 
  • Space Group: P 41 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.39α = 90
b = 84.39β = 90
c = 122.13γ = 90
Software Package:
Software NamePurpose

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

  • Released Date: 2015-03-18 
  • Deposition Author(s): Blaise, M.

Revision History  (Full details and data files)

  • Version 1.0: 2015-03-18
    Type: Initial release
  • Version 1.1: 2015-03-25
    Changes: Database references
  • Version 1.2: 2015-06-10
    Changes: Database references
  • Version 1.3: 2017-07-12
    Changes: Refinement description
  • Version 1.4: 2024-05-08
    Changes: Advisory, Data collection, Database references, Derived calculations, Other, Structure summary