3ITW

Crystal structure of TioX from Micromonospora sp. ML1

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.234 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history. 


Literature

A New Scaffold of an Old Protein Fold Ensures Binding to the Bisintercalator Thiocoraline.

Biswas, T., Zolova, O.E., Lombo, F., de la Calle, F., Salas, J.A., Tsodikov, O.V., Garneau-Tsodikova, S.

(2010) J Mol Biol 397: 495-507

  • DOI: 10.1016/j.jmb.2010.01.053
  • Primary Citation of Related Structures:  
    3ITW

  • PubMed Abstract: 

    • Thiocoraline is a thiodepsipeptide with potent antitumor activity. TioX, a protein with an unidentified function, is encoded by a gene of the thiocoraline biosynthetic gene cluster. The crystal structure of the full-length TioX protein at 2.15 A resolution reveals that TioX protomer shares an ancient betaalphabetabetabeta fold motif with glyoxalase I and bleomycin resistance protein families, despite a very low sequence homology ...

    Thiocoraline is a thiodepsipeptide with potent antitumor activity. TioX, a protein with an unidentified function, is encoded by a gene of the thiocoraline biosynthetic gene cluster. The crystal structure of the full-length TioX protein at 2.15 A resolution reveals that TioX protomer shares an ancient betaalphabetabetabeta fold motif with glyoxalase I and bleomycin resistance protein families, despite a very low sequence homology. Intriguingly, four TioX monomers form a unique 2-fold symmetric tetrameric assembly that is stabilized by four intermolecular disulfide bonds formed cyclically between Cys60 and Cys66 of adjacent monomers. The arrangement of two of the four monomers in the TioX tetramer is analogous to that in dimeric bleomycin resistance proteins. This analogy indicates that this novel higher-order structural scaffold of TioX may have evolved to bind thiocoraline. Our equilibrium titration studies demonstrate the binding of a thiocoraline chromophore analog, quinaldic acid, to TioX, thereby substantiating this model. Furthermore, a strain of Streptomyces albus containing an exogenous thiocoraline gene cluster devoid of functional tioX maintains thiocoraline production, albeit with a lower yield. Taken together, these observations rule out a direct enzymatic function of TioX and suggest that TioX is involved in thiocoraline resistance or secretion.

    Organizational Affiliation: 

    Department of Medicinal Chemistry, University of Michigan, Ann Arbor, MI 48109, USA.



Macromolecules
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(by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Protein tioXA, B137Micromonospora sp. ML1Mutation(s): 0 
Gene Names: tioX
UniProt
Find proteins for Q333U2 (Micromonospora sp. ML1)
Explore Q333U2 
Go to UniProtKB:  Q333U2
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ333U2
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.234 
  • Space Group: I 41 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 109.321α = 90
b = 109.321β = 90
c = 143.333γ = 90
Software Package:
Software NamePurpose
SOLVEphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-02-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Refinement description, Version format compliance