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STRUCTURE DETERMINATION AND REFINEMENT OF HOMOTETRAMERIC HEMOGLOBIN FROM URECHIS CAUPO AT 2.5 ANGSTROMS RESOLUTION

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.5 Å
  • R-Value Work: 0.147 

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

Literature

Structure determination and refinement of homotetrameric hemoglobin from Urechis caupo at 2.5 A resolution.

Kolatkar, P.R., Ernst, S.R., Hackert, M.L., Ogata, C.M., Hendrickson, W.A., Merritt, E.A., Phizackerley, R.P.

(1992) Acta Crystallogr.,Sect.B 48: 191-199


  • PubMed Abstract: 

    • A 5 A resolution multiple isomorphous replacement solution for hemoglobin isolated from Urechis caupo revealed a previously unobserved quaternary structure for tetrameric hemoglobin [Kolatkar, Meador, Stanfield & Hackert (1988). J. Biol. Chem. 263(7) ...

    A 5 A resolution multiple isomorphous replacement solution for hemoglobin isolated from Urechis caupo revealed a previously unobserved quaternary structure for tetrameric hemoglobin [Kolatkar, Meador, Stanfield & Hackert (1988). J. Biol. Chem. 263(7), 3462-3465]. We report here the structure of Urechis hemoglobin in the cyanomet state refined to 2.5 A resolution by simulated annealing yielding R = 0.148 for reflections F greater than 3 sigma between 5.0 and 2.5 A resolution. The starting model was fitted to a map originally derived from multiple-wavelength anomalous-dispersion phases to 3 A resolution that was then subjected to cyclic twofold molecular averaging and solvent flattening. Structural analysis of the resultant model shows that the unique quaternary assemblage is possible due to several favorable interactions between subunits, including salt links, hydrophobic pockets and interactions mediated by bound water. The tetramer is stabilized by subunit-subunit interactions between the G/H turns and D helices within the crystallographic dimer, and the A/B turn regions and E helices between subunits related by a molecular twofold axis. Interestingly, each subunit has one cysteine residue (Cys21) located in the A/B turn. These twofold-related cysteinyl residues are near enough to one another to form a disulfide bridge but do not.

    Related Citations: 
    • Novel Subunit Structure Observed for Noncooperative Hemoglobin from Urechis Caupo
      Kolatkar, P.R.,Meador, W.E.,Stanfield, R.L.,Hackert, M.L.
      (1988) J.Biol.Chem. 263: 3462

    Organizational Affiliation: 

    Department of Chemistry and Biochemistry, University of Texas, Austin 78712.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HEMOGLOBIN (CYANO MET)
A, B
141Urechis caupoMutation(s): 0 
Find proteins for P06148 (Urechis caupo)
Go to UniProtKB:  P06148
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CYN
Query on CYN
Download SDF File 
Download CCD File 
A, B
CYANIDE ION
C N
XFXPMWWXUTWYJX-UHFFFAOYSA-N
 Ligand Interaction
HEM
Query on HEM
Download SDF File 
Download CCD File 
A, B
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: 2.5 Å
  • R-Value Work: 0.147 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 104.800α = 90.00
b = 54.900β = 90.00
c = 110.600γ = 90.00
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORphasing
X-PLORrefinement

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1993-10-31
    Type: Initial release
  • Version 1.1: 2008-03-03
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance