1Z9W

Tetrameric structure of apo-7,8-Dihydroneopterin Aldolase from Mycobacterium tuberculosis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.179 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Regulation by oligomerization in a mycobacterial folate biosynthetic enzyme.

Goulding, C.W.Apostol, M.I.Sawaya, M.R.Phillips, M.Parseghian, A.Eisenberg, D.

(2005) J.Mol.Biol. 349: 61-72

  • DOI: 10.1016/j.jmb.2005.03.023
  • Primary Citation of Related Structures:  1NBU

  • PubMed Abstract: 
  • Folate derivatives are essential cofactors in the biosynthesis of purines, pyrimidines and amino acids across all forms of life. Mammals uptake folate from their diets, whereas most bacteria must synthesize folate de novo. Therefore, the enzymes in t ...

    Folate derivatives are essential cofactors in the biosynthesis of purines, pyrimidines and amino acids across all forms of life. Mammals uptake folate from their diets, whereas most bacteria must synthesize folate de novo. Therefore, the enzymes in the folate biosynthetic pathway are attractive drug targets against bacterial pathogens such as Mycobacterium tuberculosis, the cause of the world's most deadly infectious disease, tuberculosis (TB). M.tuberculosis 7,8-dihydroneopterin aldolase (Mtb FolB, DHNA) is the second enzyme in the folate biosynthetic pathway, which catalyzes the conversion of 7,8-dihydroneopterin to 6-hydroxymethyl-7,8-dihydropterin and glycoaldehyde. The 1.6A X-ray crystal structure of Mtb FolB complexed with its product, 6-hydroxymethyl-7,8-dihydropterin, reveals an octameric assembly similar to that seen in crystal structures of other FolB homologs. However, the 2.5A crystal structure of unliganded Mtb FolB reveals a novel tetrameric oligomerization state, with only partially formed active sites. A substrate induced conformational change appears to be necessary to convert the inactive tetramer to the active octamer. Ultracentrifugation confirmed that in solution unliganded Mtb FolB is mainly tetrameric and upon addition of substrate FolB is predominantly octameric. Kinetic analysis of substrate binding gives a Hill coefficient of 2.0, indicating positive cooperativity. We hypothesize that Mtb FolB displays cooperativity in substrate binding to regulate the cellular concentration of 7,8-dihydroneopterin, so that it may function not only as a precursor to folate but also as an antioxidant for the survival of M.tuberculosis against host defenses.


    Organizational Affiliation

    Molecular Biology Institute UCLA-DOE Institute of Genomics and Proteomics, P.O. Box 951570, Los Angeles, CA 90095-1570, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Dihydroneopterin aldolase
A
133Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv)Gene Names: folB
EC: 4.1.2.25, 1.13.11.81, 5.1.99.8
Find proteins for P9WNC5 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Go to UniProtKB:  P9WNC5
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.179 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 72.957α = 90.00
b = 72.957β = 90.00
c = 42.868γ = 90.00
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
EPMRphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-04-19
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Derived calculations, Version format compliance