Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis

Mycobacterium tuberculosis truncated hemoglobin, HbN, is endowed with a potent nitric-oxide dioxygenase activity and has been found to relieve nitrosative stress and enhance in vivo survival of a heterologous host, Salmonella enterica Typhimurium, within the macrophages. These findings implicate inv...

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Publicado:	2009
Materias:	Active site Dioxygenase In-vivo M. tuberculosis Molecular dynamics simulations Mycobacterium smegmatis Mycobacterium tuberculosis Nitrosative stress Protein dynamics Salmonella enterica Truncated hemoglobins Detoxification Dynamics Ligands Molecular dynamics Nitric oxide Porphyrins Hemoglobin dioxygenase heme hemoglobin HbN nitric oxide truncated hemoglobin unclassified drug mutant protein scavenger amino terminal sequence article controlled study detoxification enzyme active site enzyme activity ligand binding molecular dynamics nitric oxide scavenging nitrosative stress nonhuman Pre A motif priority journal protein analysis protein folding protein function protein interaction protein metabolism protein motif protein structure protein transport stoichiometry amino acid sequence chemical structure chemistry circular dichroism computer simulation drug effect Escherichia coli gene deletion metabolism molecular genetics oxidation reduction reaction pliability protein secondary structure structure activity relation thermodynamics X ray crystallography Amino Acid Motifs Amino Acid Sequence Circular Dichroism Computer Simulation Crystallography, X-Ray Free Radical Scavengers Models, Molecular Molecular Sequence Data Mutant Proteins Nitric Oxide Oxidation-Reduction Pliability Protein Structure, Secondary Sequence Deletion Structure-Activity Relationship Thermodynamics Truncated Hemoglobins
Acceso en línea:	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v284_n21_p14457_Lama http://hdl.handle.net/20.500.12110/paper_00219258_v284_n21_p14457_Lama
Aporte de:	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires

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spelling	paper:paper_00219258_v284_n21_p14457_Lama2023-06-08T14:43:30Z Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis Active site Dioxygenase In-vivo M. tuberculosis Molecular dynamics simulations Mycobacterium smegmatis Mycobacterium tuberculosis Nitrosative stress Protein dynamics Salmonella enterica Truncated hemoglobins Detoxification Dynamics Ligands Molecular dynamics Nitric oxide Porphyrins Hemoglobin dioxygenase heme hemoglobin HbN nitric oxide truncated hemoglobin unclassified drug mutant protein nitric oxide scavenger truncated hemoglobin amino terminal sequence article controlled study detoxification enzyme active site enzyme activity ligand binding molecular dynamics Mycobacterium smegmatis Mycobacterium tuberculosis nitric oxide scavenging nitrosative stress nonhuman Pre A motif priority journal protein analysis protein folding protein function protein interaction protein metabolism protein motif protein structure protein transport stoichiometry amino acid sequence chemical structure chemistry circular dichroism computer simulation drug effect Escherichia coli gene deletion metabolism molecular genetics oxidation reduction reaction pliability protein motif protein secondary structure structure activity relation thermodynamics X ray crystallography Mycobacterium smegmatis Mycobacterium tuberculosis Salmonella enterica Amino Acid Motifs Amino Acid Sequence Circular Dichroism Computer Simulation Crystallography, X-Ray Escherichia coli Free Radical Scavengers Models, Molecular Molecular Sequence Data Mutant Proteins Mycobacterium smegmatis Mycobacterium tuberculosis Nitric Oxide Oxidation-Reduction Pliability Protein Structure, Secondary Sequence Deletion Structure-Activity Relationship Thermodynamics Truncated Hemoglobins Mycobacterium tuberculosis truncated hemoglobin, HbN, is endowed with a potent nitric-oxide dioxygenase activity and has been found to relieve nitrosative stress and enhance in vivo survival of a heterologous host, Salmonella enterica Typhimurium, within the macrophages. These findings implicate involvement of HbN in the defense of M. tuberculosis against nitrosative stress. The protein carries a tunnel system composed of a short and a long tunnel branch that has been proposed to facilitate diatomic ligand migration to the heme and an unusual Pre-A motif at the N terminus, which does not contribute significantly to the structural integrity of the protein, as it protrudes out of the compact globin fold. Strikingly, deletion of Pre-A region from the M. tuberculosis HbN drastically reduces its ability to scavenge nitric oxide (NO), whereas its insertion at the N terminus of Pre-A lacking HbN of Mycobacterium smegmatis improved its nitric-oxide dioxygenase activity. Titration of the oxygenated adduct of HbN and its mutants with NO indicated that the stoichiometric oxidation of protein is severalfold slower when the Pre-A region is deleted in HbN. Molecular dynamics simulations show that the excision of Pre-A motif results in distinct changes in the protein dynamics, which cause the gate of the tunnel long branch to be trapped into a closed conformation, thus impeding migration of diatomic ligands toward the heme active site. The present study, thus, unequivocally demonstrates vital function of Pre-A region in NO scavenging and unravels its unique role by which HbN might attain its efficient NO-detoxification ability. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc. 2009 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v284_n21_p14457_Lama http://hdl.handle.net/20.500.12110/paper_00219258_v284_n21_p14457_Lama
institution	Universidad de Buenos Aires
institution_str	I-28
repository_str	R-134
collection	Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic	Active site Dioxygenase In-vivo M. tuberculosis Molecular dynamics simulations Mycobacterium smegmatis Mycobacterium tuberculosis Nitrosative stress Protein dynamics Salmonella enterica Truncated hemoglobins Detoxification Dynamics Ligands Molecular dynamics Nitric oxide Porphyrins Hemoglobin dioxygenase heme hemoglobin HbN nitric oxide truncated hemoglobin unclassified drug mutant protein nitric oxide scavenger truncated hemoglobin amino terminal sequence article controlled study detoxification enzyme active site enzyme activity ligand binding molecular dynamics Mycobacterium smegmatis Mycobacterium tuberculosis nitric oxide scavenging nitrosative stress nonhuman Pre A motif priority journal protein analysis protein folding protein function protein interaction protein metabolism protein motif protein structure protein transport stoichiometry amino acid sequence chemical structure chemistry circular dichroism computer simulation drug effect Escherichia coli gene deletion metabolism molecular genetics oxidation reduction reaction pliability protein motif protein secondary structure structure activity relation thermodynamics X ray crystallography Mycobacterium smegmatis Mycobacterium tuberculosis Salmonella enterica Amino Acid Motifs Amino Acid Sequence Circular Dichroism Computer Simulation Crystallography, X-Ray Escherichia coli Free Radical Scavengers Models, Molecular Molecular Sequence Data Mutant Proteins Mycobacterium smegmatis Mycobacterium tuberculosis Nitric Oxide Oxidation-Reduction Pliability Protein Structure, Secondary Sequence Deletion Structure-Activity Relationship Thermodynamics Truncated Hemoglobins
spellingShingle	Active site Dioxygenase In-vivo M. tuberculosis Molecular dynamics simulations Mycobacterium smegmatis Mycobacterium tuberculosis Nitrosative stress Protein dynamics Salmonella enterica Truncated hemoglobins Detoxification Dynamics Ligands Molecular dynamics Nitric oxide Porphyrins Hemoglobin dioxygenase heme hemoglobin HbN nitric oxide truncated hemoglobin unclassified drug mutant protein nitric oxide scavenger truncated hemoglobin amino terminal sequence article controlled study detoxification enzyme active site enzyme activity ligand binding molecular dynamics Mycobacterium smegmatis Mycobacterium tuberculosis nitric oxide scavenging nitrosative stress nonhuman Pre A motif priority journal protein analysis protein folding protein function protein interaction protein metabolism protein motif protein structure protein transport stoichiometry amino acid sequence chemical structure chemistry circular dichroism computer simulation drug effect Escherichia coli gene deletion metabolism molecular genetics oxidation reduction reaction pliability protein motif protein secondary structure structure activity relation thermodynamics X ray crystallography Mycobacterium smegmatis Mycobacterium tuberculosis Salmonella enterica Amino Acid Motifs Amino Acid Sequence Circular Dichroism Computer Simulation Crystallography, X-Ray Escherichia coli Free Radical Scavengers Models, Molecular Molecular Sequence Data Mutant Proteins Mycobacterium smegmatis Mycobacterium tuberculosis Nitric Oxide Oxidation-Reduction Pliability Protein Structure, Secondary Sequence Deletion Structure-Activity Relationship Thermodynamics Truncated Hemoglobins Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis
topic_facet	Active site Dioxygenase In-vivo M. tuberculosis Molecular dynamics simulations Mycobacterium smegmatis Mycobacterium tuberculosis Nitrosative stress Protein dynamics Salmonella enterica Truncated hemoglobins Detoxification Dynamics Ligands Molecular dynamics Nitric oxide Porphyrins Hemoglobin dioxygenase heme hemoglobin HbN nitric oxide truncated hemoglobin unclassified drug mutant protein nitric oxide scavenger truncated hemoglobin amino terminal sequence article controlled study detoxification enzyme active site enzyme activity ligand binding molecular dynamics Mycobacterium smegmatis Mycobacterium tuberculosis nitric oxide scavenging nitrosative stress nonhuman Pre A motif priority journal protein analysis protein folding protein function protein interaction protein metabolism protein motif protein structure protein transport stoichiometry amino acid sequence chemical structure chemistry circular dichroism computer simulation drug effect Escherichia coli gene deletion metabolism molecular genetics oxidation reduction reaction pliability protein motif protein secondary structure structure activity relation thermodynamics X ray crystallography Mycobacterium smegmatis Mycobacterium tuberculosis Salmonella enterica Amino Acid Motifs Amino Acid Sequence Circular Dichroism Computer Simulation Crystallography, X-Ray Escherichia coli Free Radical Scavengers Models, Molecular Molecular Sequence Data Mutant Proteins Mycobacterium smegmatis Mycobacterium tuberculosis Nitric Oxide Oxidation-Reduction Pliability Protein Structure, Secondary Sequence Deletion Structure-Activity Relationship Thermodynamics Truncated Hemoglobins
description	Mycobacterium tuberculosis truncated hemoglobin, HbN, is endowed with a potent nitric-oxide dioxygenase activity and has been found to relieve nitrosative stress and enhance in vivo survival of a heterologous host, Salmonella enterica Typhimurium, within the macrophages. These findings implicate involvement of HbN in the defense of M. tuberculosis against nitrosative stress. The protein carries a tunnel system composed of a short and a long tunnel branch that has been proposed to facilitate diatomic ligand migration to the heme and an unusual Pre-A motif at the N terminus, which does not contribute significantly to the structural integrity of the protein, as it protrudes out of the compact globin fold. Strikingly, deletion of Pre-A region from the M. tuberculosis HbN drastically reduces its ability to scavenge nitric oxide (NO), whereas its insertion at the N terminus of Pre-A lacking HbN of Mycobacterium smegmatis improved its nitric-oxide dioxygenase activity. Titration of the oxygenated adduct of HbN and its mutants with NO indicated that the stoichiometric oxidation of protein is severalfold slower when the Pre-A region is deleted in HbN. Molecular dynamics simulations show that the excision of Pre-A motif results in distinct changes in the protein dynamics, which cause the gate of the tunnel long branch to be trapped into a closed conformation, thus impeding migration of diatomic ligands toward the heme active site. The present study, thus, unequivocally demonstrates vital function of Pre-A region in NO scavenging and unravels its unique role by which HbN might attain its efficient NO-detoxification ability. © 2009 by The American Society for Biochemistry and Molecular Biology, Inc.
title	Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis
title_short	Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis
title_full	Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis
title_fullStr	Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis
title_full_unstemmed	Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis
title_sort	role of pre-a motif in nitric oxide scavenging by truncated hemoglobin, hbn, of mycobacterium tuberculosis
publishDate	2009
url	https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00219258_v284_n21_p14457_Lama http://hdl.handle.net/20.500.12110/paper_00219258_v284_n21_p14457_Lama
_version_	1768544395081023488

Role of pre-A motif in nitric oxide scavenging by truncated hemoglobin, HbN, of Mycobacterium tuberculosis

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