1CIK

RECOMBINANT SPERM WHALE MYOGLOBIN I99A MUTANT (MET)

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.193 
  • R-Value Observed: 0.153 

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history. 


Literature

Waterproofing the heme pocket. Role of proximal amino acid side chains in preventing hemin loss from myoglobin.

Liong, E.C., Dou, Y., Scott, E.E., Olson, J.S., Phillips Jr., G.N.

(2001) J Biol Chem 276: 9093-9100

  • DOI: 10.1074/jbc.M008593200
  • Primary Citation of Related Structures:  
    1CH5, 1CH3, 1CH2, 1CH1, 1CH9, 1CH7, 1CIK, 1CIO, 1CO9, 1CO8, 1CP5, 1CP0, 1CPW, 1DTI

  • PubMed Abstract: 

    • The ability of myoglobin to bind oxygen reversibly depends critically on retention of the heme prosthetic group. Globin side chains at the Leu(89)(F4), His(97)(FG3), Ile(99)(FG5), and Leu(104)(G5) positions on the proximal side of the heme pocket strongly influence heme affinity ...

    The ability of myoglobin to bind oxygen reversibly depends critically on retention of the heme prosthetic group. Globin side chains at the Leu(89)(F4), His(97)(FG3), Ile(99)(FG5), and Leu(104)(G5) positions on the proximal side of the heme pocket strongly influence heme affinity. The roles of these amino acids in preventing heme loss have been examined by determining high resolution structures of 14 different mutants at these positions using x-ray crystallography. Leu(89) and His(97) are important surface amino acids that interact either sterically or electrostatically with the edges of the porphyrin ring. Ile(99) and Leu(104) are located in the interior region of the proximal pocket beneath ring C of the heme prosthetic group. The apolar amino acids Leu(89), Ile(99), and Leu(104) "waterproof" the heme pocket by forming a barrier to solvent penetration, minimizing the size of the proximal cavity, and maintaining a hydrophobic environment. Substitutions with smaller or polar side chains at these positions result in exposure of the heme to solvent, the appearance of crystallographically defined water molecules in or near the proximal pocket, and large increases in the rate of hemin loss. Thus, the naturally occurring amino acid side chains at these positions serve to prevent hydration of the His(93)-Fe(III) bond and are highly conserved in all known myoglobins and hemoglobins.

    Organizational Affiliation: 

    Department of Biochemistry and Cell Biology and the W. M. Keck Center for Computational Biology, Rice University, Houston, Texas 77005, USA.



Macromolecules
Find similar proteins by: 
(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
PROTEIN (MYOGLOBIN)A154Physeter catodonMutation(s): 2 
Gene Names: MB
UniProt
Find proteins for P02185 (Physeter macrocephalus)
Explore P02185 
Go to UniProtKB:  P02185
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM (Subject of Investigation/LOI)
Query on HEM
Download Ideal Coordinates CCD File 
 C [auth A]PROTOPORPHYRIN IX CONTAINING FE
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L		 Ligand Interaction
SO4
Query on SO4
Download Ideal Coordinates CCD File 
 B [auth A]SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 0.193 
  • R-Value Observed: 0.153 
  • Space Group: P 6
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 91.497α = 90
b = 91.497β = 90
c = 45.944γ = 120
Software Package:
Software NamePurpose
SHELXSphasing
SHELXL-97refinement
XDSdata reduction
XSCALEdata scaling

Structure Validation

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Ligand Structure Quality Assessment  


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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-04-09
    Type: Initial release
  • Version 1.1: 2008-04-26
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance