4H07

Complex of G65T Myoglobin with Phenol in its Proximal Cavity


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.14 Å
  • R-Value Free: 0.153 
  • R-Value Work: 0.133 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Complex of myoglobin with phenol bound in a proximal cavity.

Huang, X.Wang, C.Celeste, L.R.Lovelace, L.L.Sun, S.Dawson, J.H.Lebioda, L.

(2012) Acta Crystallogr.,Sect.F 68: 1465-1471

  • DOI: 10.1107/S1744309112045514
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Sperm whale myoglobin (Mb) has weak dehaloperoxidase activity and catalyzes the peroxidative dehalogenation of 2,4,6-trichlorophenol (TCP) to 2,6-dichloroquinone. Crystals of Mb and of its more active G65T variant were used to study the binding of TC ...

    Sperm whale myoglobin (Mb) has weak dehaloperoxidase activity and catalyzes the peroxidative dehalogenation of 2,4,6-trichlorophenol (TCP) to 2,6-dichloroquinone. Crystals of Mb and of its more active G65T variant were used to study the binding of TCP, 4-iodophenol (4-IP) and phenol. The structures of crystals soaked overnight in a 10 mM solution of phenol revealed that a phenol molecule binds in the proximal cavity, forming a hydrogen bond to the hydroxyl of Tyr146 and hydrophobic contacts which include interactions with Cβ and Cγ of the proximal histidine His93. The phenol position corresponds to the strongest xenon binding site, Xe1. It appears that the ligand enters the proximal cavity through a gate formed by the flexible loops 79-86 and 93-103. TCP and 4-IP do not bind to Mb in this manner under similar conditions; however, it appears to be likely that dimethyl sulfoxide (DMSO), which was used at a concentration of 0.8 M to facilitate 4-IP dissolution, binds in the phenol/Xe1 binding site. In this structure, a water molecule coordinated to the heme iron was replaced by an oxygen molecule, reflecting the reduction of the heme. Crystals of Mb and G65T Mb soaked for 5-10 min did not show bound phenol. Kinetic studies of TCP dechlorination showed that phenol has a dual effect: it acts as a competitive inhibitor that is likely to interfere with TCP binding at the heme edge and as a weak activator, likely through binding in the proximal cavity. The lack of phenol bound at the heme edge in the crystal structures suggests that its inhibitory binding only takes place when the heme is activated by hydrogen peroxide.


    Organizational Affiliation

    Department of Chemistry and Biochemistry, University of South Carolina, Columbia, SC 20208, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Myoglobin
A
154Physeter catodonMutation(s): 1 
Gene Names: MB
Find proteins for P02185 (Physeter catodon)
Go to Gene View: MB
Go to UniProtKB:  P02185
Small Molecules
Ligands 4 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

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

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Download CCD File 
A
PHENOL
C6 H6 O
ISWSIDIOOBJBQZ-UHFFFAOYSA-N
 Ligand Interaction
EDO
Query on EDO

Download SDF File 
Download CCD File 
A
1,2-ETHANEDIOL
ETHYLENE GLYCOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
 Ligand Interaction
HEM
Query on HEM

Download SDF File 
Download CCD File 
A
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: 1.14 Å
  • R-Value Free: 0.153 
  • R-Value Work: 0.133 
  • Space Group: P 6
Unit Cell:
Length (Å)Angle (°)
a = 90.531α = 90.00
b = 90.531β = 90.00
c = 45.158γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
SERGUIdata collection
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-11-21
    Type: Initial release
  • Version 1.1: 2012-12-12
    Type: Database references
  • Version 1.2: 2017-11-15
    Type: Refinement description