1Z75

Crystal Structure of ArnA dehydrogenase (decarboxylase) domain, R619M mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.203 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structure and Mechanism of ArnA: Conformational Change Implies Ordered Dehydrogenase Mechanism in Key Enzyme for Polymyxin Resistance

Gatzeva-Topalova, P.Z.May, A.P.Sousa, M.C.

(2005) Structure 13: 929-942

  • DOI: 10.1016/j.str.2005.03.018
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The modification of lipid A with 4-amino-4-deoxy-L-arabinose (Ara4N) allows gram-negative bacteria to resist the antimicrobial activity of cationic antimicrobial peptides and antibiotics such as polymyxin. ArnA is the first enzyme specific to the lip ...

    The modification of lipid A with 4-amino-4-deoxy-L-arabinose (Ara4N) allows gram-negative bacteria to resist the antimicrobial activity of cationic antimicrobial peptides and antibiotics such as polymyxin. ArnA is the first enzyme specific to the lipid A-Ara4N pathway. It contains two functionally and physically separable domains: a dehydrogenase domain (ArnA_DH) catalyzing the NAD+-dependent oxidative decarboxylation of UDP-Glucuronic acid (UDP-GlcA), and a transformylase domain that formylates UDP-Ara4N. Here, we describe the crystal structure of the full-length bifunctional ArnA with UDP-GlcA and ATP bound to the dehydrogenase domain. Binding of UDP-GlcA triggers a 17 A conformational change in ArnA_DH that opens the NAD+ binding site while trapping UDP-GlcA. We propose an ordered mechanism of substrate binding and product release. Mutation of residues R619 and S433 demonstrates their importance in catalysis and suggests that R619 functions as a general acid in catalysis. The proposed mechanism for ArnA_DH has important implications for the design of selective inhibitors.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, Colorado 80309, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
protein ArnA
A
358Escherichia coli (strain K12)Mutation(s): 1 
Gene Names: arnA (pmrI, yfbG)
Find proteins for P77398 (Escherichia coli (strain K12))
Go to UniProtKB:  P77398
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
GOL
Query on GOL

Download SDF File 
Download CCD File 
A
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.231 
  • R-Value Work: 0.203 
  • Space Group: P 41 3 2
Unit Cell:
Length (Å)Angle (°)
a = 150.364α = 90.00
b = 150.364β = 90.00
c = 150.364γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
CNSphasing
SCALEPACKdata scaling
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-06-07
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance