Ultrafast heme–ligand recombination in truncated hemoglobin HbO from Mycobacterium tuberculosis: A ligand cage
| Autor: | Joel M. Friedman, Marten H. Vos, Hugues Ouellet, Audrius Jasaitis, Michel Guertin, Jean-Louis Martin, Jean Christophe Lambry |
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| Přispěvatelé: | Laboratoire d'optique et biosciences (LOB), École polytechnique (X)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Department of Biochemistry, Microbiology and Bioinformatics, Université Laval [Québec] (ULaval), Department of Physiology and Biophysics, Albert Einstein College of Medicine [New York] |
| Rok vydání: | 2012 |
| Předmět: |
0303 health sciences
Hemeprotein Chemistry Stereochemistry Ligand General Physics and Astronomy 010402 general chemistry 01 natural sciences Diatomic molecule 0104 chemical sciences 3. Good health 03 medical and health sciences chemistry.chemical_compound Molecular dynamics Molecule Reactivity (chemistry) Hemoglobin Physical and Theoretical Chemistry Heme 030304 developmental biology |
| Zdroj: | Chemical Physics Chemical Physics, Elsevier, 2012, 396, pp.10-16. ⟨10.1016/j.chemphys.2011.04.003⟩ |
| ISSN: | 0301-0104 |
| DOI: | 10.1016/j.chemphys.2011.04.003 |
| Popis: | International audience; Truncated hemoglobin HbO from Mycobacterium tuberculosis displays very slow exchange of diatomic ligands with its environment. Using femtosecond spectroscopy, we show that upon photoexcitation, ligands rebind with unusual speed and efficiency. Only ∼1% O2 can escape from the heme pocket and less than 1% NO. Most remarkably, CO rebinding occurs for 95%, predominantly in 1.2 ns. The general CO rebinding properties are unexpectedly robust against changes in the interactions with close by aromatic residues Trp88 (G8) and Tyr36 (CD1). Molecular dynamics simulations of the CO complex suggest that interactions of the ligand with structural water molecules as well as its rotational freedom play a role in the high reactivity of the ligand and the heme. The slow exchange of ligands between heme and environment may result from a combination of hindered ligand access to the heme pocket by the network of distal aromatic residues, and low escape probability from the pocket. |
| Databáze: | OpenAIRE |
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