Abstract
Truncated hemoglobins (trHbs) are low-molecular-weight oxygen-binding heme-proteins distributed in eubacteria, cyanobacteria, unicellular eukaryotes, and in higher plants, constituting a distinct group within the hemoglobin (Hb) superfamily. TrHbs display amino acid sequences 20-40 residues shorter than classical (non)vertebrate Hbs and myoglobins, to which they are scarcely related by sequence similarity. The trHb tertiary structure is based on a 2-on-2 α-helical sandwich, which represents a striking editing of the highly conserved 3-on-3 α-helical globin fold, achieved through deletion/truncation of α-helices and specific residue substitutions. Despite their 'minimal' polypeptide chain span, trHbs display an inner tunnel/cavity system held to support ligand diffusion to/from the heme distal pocket, accumulation of heme ligands within the protein matrix, and/or multiligand reactions. Moreover, trHbs bind and effectively stabilize the heme and recognize diatomic ligands (i.e., O 2, CO, NO, and cyanide), albeit with varying thermodynamic and kinetic parameters. Here, structural bases for heme binding and diatomic ligand recognition by trHbs are reviewed.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 97-109 |
| Number of pages | 13 |
| Journal | Journal of Inorganic Biochemistry |
| Volume | 99 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 2005 |
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Keywords
- Diatomic ligand recognition
- Heme stabilization
- Hemoglobin
- Myoglobin
- Protein cavities
- Truncated hemoglobin
ASJC Scopus subject areas
- Biochemistry
- Inorganic Chemistry
Cite this
Structural bases for heme binding and diatomic ligand recognition in truncated hemoglobins. / Milani, Mario; Pesce, Alessandra; Nardini, Marco; Ouellet, Hugues; Ouellet, Yannick; Dewilde, Sylvia; Bocedi, Alessio; Ascenzi, Paolo; Guertin, Michel; Moens, Luc; Friedman, Joel M.; Wittenberg, Jonathan B.; Bolognesi, Martino.
In: Journal of Inorganic Biochemistry, Vol. 99, No. 1, 01.2005, p. 97-109.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Structural bases for heme binding and diatomic ligand recognition in truncated hemoglobins
AU - Milani, Mario
AU - Pesce, Alessandra
AU - Nardini, Marco
AU - Ouellet, Hugues
AU - Ouellet, Yannick
AU - Dewilde, Sylvia
AU - Bocedi, Alessio
AU - Ascenzi, Paolo
AU - Guertin, Michel
AU - Moens, Luc
AU - Friedman, Joel M.
AU - Wittenberg, Jonathan B.
AU - Bolognesi, Martino
PY - 2005/1
Y1 - 2005/1
N2 - Truncated hemoglobins (trHbs) are low-molecular-weight oxygen-binding heme-proteins distributed in eubacteria, cyanobacteria, unicellular eukaryotes, and in higher plants, constituting a distinct group within the hemoglobin (Hb) superfamily. TrHbs display amino acid sequences 20-40 residues shorter than classical (non)vertebrate Hbs and myoglobins, to which they are scarcely related by sequence similarity. The trHb tertiary structure is based on a 2-on-2 α-helical sandwich, which represents a striking editing of the highly conserved 3-on-3 α-helical globin fold, achieved through deletion/truncation of α-helices and specific residue substitutions. Despite their 'minimal' polypeptide chain span, trHbs display an inner tunnel/cavity system held to support ligand diffusion to/from the heme distal pocket, accumulation of heme ligands within the protein matrix, and/or multiligand reactions. Moreover, trHbs bind and effectively stabilize the heme and recognize diatomic ligands (i.e., O 2, CO, NO, and cyanide), albeit with varying thermodynamic and kinetic parameters. Here, structural bases for heme binding and diatomic ligand recognition by trHbs are reviewed.
AB - Truncated hemoglobins (trHbs) are low-molecular-weight oxygen-binding heme-proteins distributed in eubacteria, cyanobacteria, unicellular eukaryotes, and in higher plants, constituting a distinct group within the hemoglobin (Hb) superfamily. TrHbs display amino acid sequences 20-40 residues shorter than classical (non)vertebrate Hbs and myoglobins, to which they are scarcely related by sequence similarity. The trHb tertiary structure is based on a 2-on-2 α-helical sandwich, which represents a striking editing of the highly conserved 3-on-3 α-helical globin fold, achieved through deletion/truncation of α-helices and specific residue substitutions. Despite their 'minimal' polypeptide chain span, trHbs display an inner tunnel/cavity system held to support ligand diffusion to/from the heme distal pocket, accumulation of heme ligands within the protein matrix, and/or multiligand reactions. Moreover, trHbs bind and effectively stabilize the heme and recognize diatomic ligands (i.e., O 2, CO, NO, and cyanide), albeit with varying thermodynamic and kinetic parameters. Here, structural bases for heme binding and diatomic ligand recognition by trHbs are reviewed.
KW - Diatomic ligand recognition
KW - Heme stabilization
KW - Hemoglobin
KW - Myoglobin
KW - Protein cavities
KW - Truncated hemoglobin
UR - http://www.scopus.com/inward/record.url?scp=10444229578&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=10444229578&partnerID=8YFLogxK
U2 - 10.1016/j.jinorgbio.2004.10.035
DO - 10.1016/j.jinorgbio.2004.10.035
M3 - Article
C2 - 15598494
AN - SCOPUS:10444229578
VL - 99
SP - 97
EP - 109
JO - Journal of Inorganic Biochemistry
JF - Journal of Inorganic Biochemistry
SN - 0162-0134
IS - 1
ER -