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Updated: Aug 10, 2026
08:53
Biochemical and Structural Characterization of the Carbohydrate Transport Substrate-binding-protein SP0092
Published on: October 2, 2017
On extended x-ray absorption fine structure studies of hemoglobin
Summary
Extended X-ray absorption fine structure (EXAFS) studies reveal the iron atom's precise position in deoxygenated hemoglobin. The iron atom is located 0.2 +/- 0.1 0.2 angstroms above the porphyrin nitrogen plane, confirming earlier findings.
Area of Science:
- Biophysics
- Structural Biology
- Biochemistry
Background:
- Hemoglobin is crucial for oxygen transport in the blood.
- Understanding the iron atom's position within hemoglobin is key to its function.
- Extended X-ray Absorption Fine Structure (EXAFS) is a powerful technique for atomic-level structural analysis.
Purpose of the Study:
- To review and clarify the iron atom's position in deoxygenated hemoglobin using EXAFS data.
- To reconcile conflicting interpretations of structural data from different studies.
- To accurately determine the iron-porphinato nitrogen distance and the iron's displacement from the porphyrin plane.
Main Methods:
- Analysis of extended x-ray absorption fine structure (EXAFS) data.
- Review of published EXAFS studies on hemoglobin.
- Triangulation methods applied to structural data.
Main Results:
- The iron-porphinato nitrogen distance was determined to be 2.06 +/- 0.01 Å by two independent investigations.
- Discrepancies in previous calculations were attributed to overlooking differences between ferrous and ferric hemes.
- The iron atom is positioned 0.2 +/- 0.1 0.2 Å above the plane of the porphyrin nitrogens.
Conclusions:
- The iron atom in deoxygenated hemoglobin is located slightly above the porphyrin nitrogen plane.
- The precise positioning of the iron atom is critical for hemoglobin's oxygen-binding capabilities.
- EXAFS studies provide accurate structural insights into metalloproteins like hemoglobin.
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