4H0B

Complex of G65T Myoglobin with DMSO in its Distal Cavity


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.26 Å
  • R-Value Free: 0.153 
  • R-Value Work: 0.127 
  • R-Value Observed: 0.128 

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This is version 1.3 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 Struct Biol Cryst Commun 68: 1465-1471

  • DOI: https://doi.org/10.1107/S1744309112045514
  • Primary Citation of Related Structures:  
    3U3E, 4H07, 4H0B

  • 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 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:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Myoglobin154Physeter catodonMutation(s): 1 
Gene Names: MB
UniProt
Find proteins for P02185 (Physeter macrocephalus)
Explore P02185 
Go to UniProtKB:  P02185
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02185
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Ligands 5 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM

Download Ideal Coordinates CCD File 
B [auth A]PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
SO4
Query on SO4

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A],
G [auth A],
H [auth A]
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
DMS
Query on DMS

Download Ideal Coordinates CCD File 
D [auth A]DIMETHYL SULFOXIDE
C2 H6 O S
IAZDPXIOMUYVGZ-UHFFFAOYSA-N
EDO
Query on EDO

Download Ideal Coordinates CCD File 
I [auth A]1,2-ETHANEDIOL
C2 H6 O2
LYCAIKOWRPUZTN-UHFFFAOYSA-N
OXY
Query on OXY

Download Ideal Coordinates CCD File 
C [auth A]OXYGEN MOLECULE
O2
MYMOFIZGZYHOMD-UHFFFAOYSA-N
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.26 Å
  • R-Value Free: 0.153 
  • R-Value Work: 0.127 
  • R-Value Observed: 0.128 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 90.499α = 90
b = 90.499β = 90
c = 45.319γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
REFMACrefinement
PDB_EXTRACTdata extraction
SERGUIdata collection

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-11-21
    Type: Initial release
  • Version 1.1: 2012-12-12
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description
  • Version 1.3: 2024-02-28
    Changes: Data collection, Database references, Derived calculations