1.75 A resolution structure of CT263-D161N (MTAN) from Chlamydia trachomatis bound to MTA

Experimental Data Snapshot

  • Resolution: 1.75 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.166 

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Structural and Biochemical Characterization of Chlamydia trachomatis Hypothetical Protein CT263 Supports That Menaquinone Synthesis Occurs through the Futalosine Pathway.

Barta, M.L.Thomas, K.Yuan, H.Lovell, S.Battaile, K.P.Schramm, V.L.Hefty, P.S.

(2014) J Biol Chem 289: 32214-32229

  • DOI: https://doi.org/10.1074/jbc.M114.594325
  • Primary Citation of Related Structures:  
    4QAQ, 4QAR, 4QAS, 4QAT, 4QFB

  • PubMed Abstract: 

    The obligate intracellular human pathogen Chlamydia trachomatis is the etiological agent of blinding trachoma and sexually transmitted disease. Genomic sequencing of Chlamydia indicated this medically important bacterium was not exclusively dependent on the host cell for energy. In order for the electron transport chain to function, electron shuttling between membrane-embedded complexes requires lipid-soluble quinones (e.g. menaquionone or ubiquinone). The sources or biosynthetic pathways required to obtain these electron carriers within C. trachomatis are poorly understood. The 1.58Å crystal structure of C. trachomatis hypothetical protein CT263 presented here supports a role in quinone biosynthesis. Although CT263 lacks sequence-based functional annotation, the crystal structure of CT263 displays striking structural similarity to 5'-methylthioadenosine nucleosidase (MTAN) enzymes. Although CT263 lacks the active site-associated dimer interface found in prototypical MTANs, co-crystal structures with product (adenine) or substrate (5'-methylthioadenosine) indicate that the canonical active site residues are conserved. Enzymatic characterization of CT263 indicates that the futalosine pathway intermediate 6-amino-6-deoxyfutalosine (kcat/Km = 1.8 × 10(3) M(-1) s(-1)), but not the prototypical MTAN substrates (e.g. S-adenosylhomocysteine and 5'-methylthioadenosine), is hydrolyzed. Bioinformatic analyses of the chlamydial proteome also support the futalosine pathway toward the synthesis of menaquinone in Chlamydiaceae. This report provides the first experimental support for quinone synthesis in Chlamydia. Menaquinone synthesis provides another target for agents to combat C. trachomatis infection.

  • Organizational Affiliation

    Industrial Macromolecular Crystallography Association-Collaborative Access Team, Hauptman-Woodward Medical Research Institute, Argonne, Illinois 60439.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
201Chlamydia trachomatis L2/434/BuMutation(s): 1 
Gene Names: CTL0515
Find proteins for A0A0H3MBV9 (Chlamydia trachomatis serovar L2 (strain 434/Bu / ATCC VR-902B))
Explore A0A0H3MBV9 
Go to UniProtKB:  A0A0H3MBV9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0H3MBV9
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on MTA

Download Ideal Coordinates CCD File 
C11 H15 N5 O3 S
Experimental Data & Validation

Experimental Data

  • Resolution: 1.75 Å
  • R-Value Free: 0.194 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.166 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 65.879α = 90
b = 104.258β = 90
c = 58.216γ = 90
Software Package:
Software NamePurpose
Aimlessdata scaling
PDB_EXTRACTdata extraction
JDirectordata collection
XDSdata reduction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-10-01
    Type: Initial release
  • Version 1.1: 2014-12-17
    Changes: Database references
  • Version 1.2: 2017-11-22
    Changes: Refinement description
  • Version 1.3: 2024-02-28
    Changes: Data collection, Database references, Derived calculations