Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N
The truncated hemoglobin N, HbN, of Mycobacterium tuberculosis is endowed with a potent nitric oxide dioxygenase (NOD) activity that allows it to relieve nitrosative stress and enhance in vivo survival of its host. Despite its small size, the protein matrix of HbN hosts a two-branched tunnel, consis...
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2012
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19326203_v7_n11_p_Oliveira http://hdl.handle.net/20.500.12110/paper_19326203_v7_n11_p_Oliveira |
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paper:paper_19326203_v7_n11_p_Oliveira2023-06-08T16:31:01Z Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N Martí, Marcelo Adrián Boechi, Leonardo Estrin, Dario Ariel alanine dioxygenase heme isoleucine nitric oxide dioxygenase oxygen phenylalanine phenylalanine 15 truncated hemoglobin truncated hemoglobin N tryptophan tyrosine unclassified drug article conformational transition controlled study detoxification down regulation enzyme activity ligand binding molecular dynamics mutant mutational analysis Mycobacterium tuberculosis nonhuman oxidation oxygen affinity site directed mutagenesis structure analysis wild type Bacterial Proteins Binding Sites Carbon Monoxide Computer Simulation Crystallography, X-Ray Ligands Mutagenesis, Site-Directed Mycobacterium tuberculosis Nitric Oxide Oxygen Phenylalanine Protein Structure, Tertiary Truncated Hemoglobins Mycobacterium tuberculosis The truncated hemoglobin N, HbN, of Mycobacterium tuberculosis is endowed with a potent nitric oxide dioxygenase (NOD) activity that allows it to relieve nitrosative stress and enhance in vivo survival of its host. Despite its small size, the protein matrix of HbN hosts a two-branched tunnel, consisting of orthogonal short and long channels, that connects the heme active site to the protein surface. A novel dual-path mechanism has been suggested to drive migration of O 2 and NO to the distal heme cavity. While oxygen migrates mainly by the short path, a ligand-induced conformational change regulates opening of the long tunnel branch for NO, via a phenylalanine (PheE15) residue that acts as a gate. Site-directed mutagenesis and molecular simulations have been used to examine the gating role played by PheE15 in modulating the NOD function of HbN. Mutants carrying replacement of PheE15 with alanine, isoleucine, tyrosine and tryptophan have similar O 2 /CO association kinetics, but display significant reduction in their NOD function. Molecular simulations substantiated that mutation at the PheE15 gate confers significant changes in the long tunnel, and therefore may affect the migration of ligands. These results support the pivotal role of PheE15 gate in modulating the diffusion of NO via the long tunnel branch in the oxygenated protein, and hence the NOD function of HbN. © 2012 Oliveira et al. Fil:Martí, M.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Boechi, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Fil:Estrin, D.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. 2012 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19326203_v7_n11_p_Oliveira http://hdl.handle.net/20.500.12110/paper_19326203_v7_n11_p_Oliveira |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
alanine dioxygenase heme isoleucine nitric oxide dioxygenase oxygen phenylalanine phenylalanine 15 truncated hemoglobin truncated hemoglobin N tryptophan tyrosine unclassified drug article conformational transition controlled study detoxification down regulation enzyme activity ligand binding molecular dynamics mutant mutational analysis Mycobacterium tuberculosis nonhuman oxidation oxygen affinity site directed mutagenesis structure analysis wild type Bacterial Proteins Binding Sites Carbon Monoxide Computer Simulation Crystallography, X-Ray Ligands Mutagenesis, Site-Directed Mycobacterium tuberculosis Nitric Oxide Oxygen Phenylalanine Protein Structure, Tertiary Truncated Hemoglobins Mycobacterium tuberculosis |
| spellingShingle |
alanine dioxygenase heme isoleucine nitric oxide dioxygenase oxygen phenylalanine phenylalanine 15 truncated hemoglobin truncated hemoglobin N tryptophan tyrosine unclassified drug article conformational transition controlled study detoxification down regulation enzyme activity ligand binding molecular dynamics mutant mutational analysis Mycobacterium tuberculosis nonhuman oxidation oxygen affinity site directed mutagenesis structure analysis wild type Bacterial Proteins Binding Sites Carbon Monoxide Computer Simulation Crystallography, X-Ray Ligands Mutagenesis, Site-Directed Mycobacterium tuberculosis Nitric Oxide Oxygen Phenylalanine Protein Structure, Tertiary Truncated Hemoglobins Mycobacterium tuberculosis Martí, Marcelo Adrián Boechi, Leonardo Estrin, Dario Ariel Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N |
| topic_facet |
alanine dioxygenase heme isoleucine nitric oxide dioxygenase oxygen phenylalanine phenylalanine 15 truncated hemoglobin truncated hemoglobin N tryptophan tyrosine unclassified drug article conformational transition controlled study detoxification down regulation enzyme activity ligand binding molecular dynamics mutant mutational analysis Mycobacterium tuberculosis nonhuman oxidation oxygen affinity site directed mutagenesis structure analysis wild type Bacterial Proteins Binding Sites Carbon Monoxide Computer Simulation Crystallography, X-Ray Ligands Mutagenesis, Site-Directed Mycobacterium tuberculosis Nitric Oxide Oxygen Phenylalanine Protein Structure, Tertiary Truncated Hemoglobins Mycobacterium tuberculosis |
| description |
The truncated hemoglobin N, HbN, of Mycobacterium tuberculosis is endowed with a potent nitric oxide dioxygenase (NOD) activity that allows it to relieve nitrosative stress and enhance in vivo survival of its host. Despite its small size, the protein matrix of HbN hosts a two-branched tunnel, consisting of orthogonal short and long channels, that connects the heme active site to the protein surface. A novel dual-path mechanism has been suggested to drive migration of O 2 and NO to the distal heme cavity. While oxygen migrates mainly by the short path, a ligand-induced conformational change regulates opening of the long tunnel branch for NO, via a phenylalanine (PheE15) residue that acts as a gate. Site-directed mutagenesis and molecular simulations have been used to examine the gating role played by PheE15 in modulating the NOD function of HbN. Mutants carrying replacement of PheE15 with alanine, isoleucine, tyrosine and tryptophan have similar O 2 /CO association kinetics, but display significant reduction in their NOD function. Molecular simulations substantiated that mutation at the PheE15 gate confers significant changes in the long tunnel, and therefore may affect the migration of ligands. These results support the pivotal role of PheE15 gate in modulating the diffusion of NO via the long tunnel branch in the oxygenated protein, and hence the NOD function of HbN. © 2012 Oliveira et al. |
| author |
Martí, Marcelo Adrián Boechi, Leonardo Estrin, Dario Ariel |
| author_facet |
Martí, Marcelo Adrián Boechi, Leonardo Estrin, Dario Ariel |
| author_sort |
Martí, Marcelo Adrián |
| title |
Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N |
| title_short |
Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N |
| title_full |
Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N |
| title_fullStr |
Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N |
| title_full_unstemmed |
Role of PheE15 Gate in Ligand Entry and Nitric Oxide Detoxification Function of Mycobacterium tuberculosis Truncated Hemoglobin N |
| title_sort |
role of phee15 gate in ligand entry and nitric oxide detoxification function of mycobacterium tuberculosis truncated hemoglobin n |
| publishDate |
2012 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_19326203_v7_n11_p_Oliveira http://hdl.handle.net/20.500.12110/paper_19326203_v7_n11_p_Oliveira |
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AT martimarceloadrian roleofphee15gateinligandentryandnitricoxidedetoxificationfunctionofmycobacteriumtuberculosistruncatedhemoglobinn AT boechileonardo roleofphee15gateinligandentryandnitricoxidedetoxificationfunctionofmycobacteriumtuberculosistruncatedhemoglobinn AT estrindarioariel roleofphee15gateinligandentryandnitricoxidedetoxificationfunctionofmycobacteriumtuberculosistruncatedhemoglobinn |
| _version_ |
1768542908154118144 |