1V5H

Crystal Structure of Human Cytoglobin (Ferric Form)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.248 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis of human cytoglobin for ligand binding.

Sugimoto, H.Makino, M.Sawai, H.Kawada, N.Yoshizato, K.Shiro, Y.

(2004) J.Mol.Biol. 339: 873-885

  • DOI: 10.1016/j.jmb.2004.04.024

  • PubMed Abstract: 
  • Cytoglobin (Cgb), a newly discovered member of the vertebrate globin family, binds O(2) reversibly via its heme, as is the case for other mammalian globins (hemoglobin (Hb), myoglobin (Mb) and neuroglobin (Ngb)). While Cgb is expressed in various tis ...

    Cytoglobin (Cgb), a newly discovered member of the vertebrate globin family, binds O(2) reversibly via its heme, as is the case for other mammalian globins (hemoglobin (Hb), myoglobin (Mb) and neuroglobin (Ngb)). While Cgb is expressed in various tissues, its physiological role is not clearly understood. Here, the X-ray crystal structure of wild type human Cgb in the ferric state at 2.4A resolution is reported. In the crystal structure, ferric Cgb is dimerized through two intermolecular disulfide bonds between Cys38(B2) and Cys83(E9), and the dimerization interface is similar to that of lamprey Hb and Ngb. The overall backbone structure of the Cgb monomer exhibits a traditional globin fold with a three-over-three alpha-helical sandwich, in which the arrangement of helices is basically the same among all globins studied to date. A detailed comparison reveals that the backbone structure of the CD corner to D helix region, the N terminus of the E-helix and the F-helix of Cgb resembles more closely those of pentacoordinated globins (Mb, lamprey Hb), rather than hexacoordinated globins (Ngb, rice Hb). However, the His81(E7) imidazole group coordinates directly to the heme iron as a sixth axial ligand to form a hexcoordinated heme, like Ngb and rice Hb. The position and orientation of the highly conserved residues in the heme pocket (Phe(CD1), Val(E11), distal His(E7) and proximal His(F8)) are similar to those of other globin proteins. Two alternative conformations of the Arg84(E10) guanidium group were observed, suggesting that it participates in ligand binding to Cgb, as is the case for Arg(E10) of Aplysia Mb and Lys(E10) of Ngb. The structural diversities and similarities among globin proteins are discussed with relevance to molecular evolutionary relationships.


    Related Citations: 
    • Characterization of the heme environmental structure of cytoglobin, a fourth globin in humans
      Sawai, H.,Kawada, N.,Yoshizato, K.,Nakajima, H.,Aono, S.,Shiro, Y.
      (2003) Biochemistry 42: 5133


    Organizational Affiliation

    Biophysical Chemistry Laboratory, Riken Harima Institute/SPring8, Hyogo 679-5148, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cytoglobin
A
193Homo sapiensGene Names: CYGB (STAP)
Find proteins for Q8WWM9 (Homo sapiens)
Go to Gene View: CYGB
Go to UniProtKB:  Q8WWM9
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
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: 2.4 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.248 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 74.401α = 90.00
b = 74.401β = 90.00
c = 59.634γ = 120.00
Software Package:
Software NamePurpose
CNSrefinement
SOLVEphasing
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2004-06-08
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance