2OHB

Myoglobin cavity mutant I107W


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.177 

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This is version 1.5 of the entry. See complete history


Literature

Ligand pathways in myoglobin: A review of trp cavity mutations.

Olson, J.S.Soman, J.Phillips, G.N.

(2007) IUBMB Life 59: 552-562

  • DOI: https://doi.org/10.1080/15216540701230495
  • Primary Citation of Related Structures:  
    2OH8, 2OH9, 2OHA, 2OHB

  • PubMed Abstract: 

    The pathways for ligand entry and exit in myoglobin have now been well established by a wide variety of experimental results, including pico- to nano- to microsecond transient absorbance measurements and time-resolved X-ray crystallographic measurements. Trp insertions have been used to block, one at a time, the three major cavities occupied by photodissociated ligands. In this work, we review the effects of the L29(B10)W mutation, which places a large indole ring in the initial 'docking site' for photodissociated ligands. Then, the effects of blocking the Xe4 site with I28W, V68W, and I107W mutations and the Xe1 cavity with L89W, L104W, and F138W mutations are described. The structures of four of these mutants are shown for the first time (Trp28, Trp68, Trp107, and Trp 138 sperm whale metMb). All available results support a 'side path' mechanism in which ligands move into and out of myoglobin by outward rotation of the HisE7 side chain, but after entry can migrate into internal cavities, including the distal Xe4 and proximal Xe1 binding sites. The distal cavities act like the pocket of a baseball glove, catching the ligand and holding it long enough for the histidine gate to close and facilitate internal coordination with the heme iron atom. The physiological role of the proximal Xe1 site is less clear because changes in the size of this cavity have minimal effects on overall O(2) binding parameters.


  • Organizational Affiliation

    Department of Biochemistry & Cell Biology, Rice University, Texas 77005-1892, USA. olson@rice.ed


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
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.177 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.56α = 90
b = 91.56β = 90
c = 46γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
PDB_EXTRACTdata extraction

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-01-23
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2021-10-20
    Changes: Database references, Derived calculations
  • Version 1.5: 2023-12-27
    Changes: Data collection