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 

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

  • 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 reso ...

    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

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Protein tioX
A, B
137Micromonospora sp. ML1Mutation(s): 0 
Gene Names: tioX
Find proteins for Q333U2 (Micromonospora sp. ML1)
Go to UniProtKB:  Q333U2
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.268 
  • R-Value Work: 0.232 
  • Space Group: I 41 2 2
Unit Cell:
Length (Å)Angle (°)
a = 109.321α = 90.00
b = 109.321β = 90.00
c = 143.333γ = 90.00
Software Package:
Software NamePurpose
SOLVEphasing
HKL-2000data scaling
REFMACrefinement
HKL-2000data reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

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