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
N1 - Funding Information:
We are grateful to Prof. P. Visca (Department of Biology, University ‘Rome Tre’, Rome, Italy) for helpful discussions. This work has been supported by grants from the Italian National Research Council (project PS-Functional Genomics, to M.B.), and from the Ministry for Education, University and Scientific Research (project RBAU015B47_002, to M.B.). M.B. is grateful to Istituto ‘Giannina Gaslini’ (Genova, Italy) and to Fondazione Compagnia di San Paolo (Torino, Italy) for continuous support. S.D. is a post-doctoral Fellow of the FWO (Fund for Scientific Research – Flanders).
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., O2, 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., O2, 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
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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 -