4KMW

Structure of the Y34N MUTANT OF DEHALOPEROXIDASE-HEMOGLOBIN A FROM AMPHITRITE ORNATA WITH 2,4,6-TRICHLOROPHENOL


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.79 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.146 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Complexes of dual-function hemoglobin/dehaloperoxidase with substrate 2,4,6-trichlorophenol are inhibitory and indicate binding of halophenol to compound I.

Wang, C.Lovelace, L.L.Sun, S.Dawson, J.H.Lebioda, L.

(2013) Biochemistry 52: 6203-6210

  • DOI: 10.1021/bi400627w
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The hemoglobin of sea worm Amphitrite ornata, which for historical reasons is abbreviated as DHP for dehaloperoxidase, has two physiological functions: it binds dioxygen in the ferrous state and dehalogenates halophenols, such as 2,4,6-trichloropheno ...

    The hemoglobin of sea worm Amphitrite ornata, which for historical reasons is abbreviated as DHP for dehaloperoxidase, has two physiological functions: it binds dioxygen in the ferrous state and dehalogenates halophenols, such as 2,4,6-trichlorophenol (TCP), using hydrogen peroxide as the oxidant in the ferric state. The crystal structures of three DHP variants (Y34N, Y34N/S91G, and L100F) with TCP bound show two mutually exclusive modes of substrate binding. One of them, the internal site, is deep inside the distal pocket with the phenolic OH moiety forming a hydrogen bond to the water molecule coordinated to the heme Fe. In this complex, the distal histidine is predominantly located in the closed position and also forms a hydrogen bond to the phenolic hydroxide. The second mode of TCP binding is external, at the heme edge, with the halophenol molecule forming a lid covering the entrance to the distal cavity. The distal histidine is in the open position and forms a hydrogen bond to the OH group of TCP, which also hydrogen bonds to the hydroxyl of Tyr38. The distance between the Cl4 atom of TCP and the heme Fe is 3.9 Å (nonbonding). In both complexes, TCP molecules prevent the approach of hydrogen peroxide to the heme, indicating that the complexes are inhibitory and implying that the substrates must bind in an ordered fashion: hydrogen peroxide first and TCP second. Kinetic studies confirmed the inhibition of DHP by high concentrations of TCP. The external binding mode may resemble the interaction of TCP with Compound I, the catalytic intermediate to which halophenols bind. The measured values of the apparent Km for TCP were in the range of 0.3-0.8 mM, much lower than the concentrations required to observe TCP binding in crystals. This indicates that during catalysis TCP binds to Compound I. Mutant F21W, which likely has the internal TCP binding site blocked, has ~7% of the activity of wild-type DHP.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of South Carolina , Columbia, South Carolina 29208, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Dehaloperoxidase A
A, B
137Amphitrite ornataMutation(s): 1 
Find proteins for Q9NAV8 (Amphitrite ornata)
Go to UniProtKB:  Q9NAV8
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
T6C
Query on T6C

Download SDF File 
Download CCD File 
A, B
2,4,6-trichlorophenol
C6 H3 Cl3 O
LINPIYWFGCPVIE-UHFFFAOYSA-N
 Ligand Interaction
SO4
Query on SO4

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

Download SDF File 
Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.79 Å
  • R-Value Free: 0.232 
  • R-Value Work: 0.146 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 58.553α = 90.00
b = 67.259β = 90.00
c = 67.890γ = 90.00
Software Package:
Software NamePurpose
PDB_EXTRACTdata extraction
SCALEPACKdata scaling
SERGUIdata collection
REFMACrefinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2013-09-04
    Type: Initial release
  • Version 1.1: 2013-09-18
    Type: Database references
  • Version 1.2: 2013-12-25
    Type: Database references
  • Version 1.3: 2017-11-15
    Type: Refinement description