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Gardner AM, Gardner PR. Dioxygen and glucose force motion of the electron-transfer switch in the iron(III) flavohemoglobin-type nitric oxide dioxygenase. J Inorg Biochem 2023; 245:112257. [PMID: 37229820 DOI: 10.1016/j.jinorgbio.2023.112257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 04/28/2023] [Accepted: 05/11/2023] [Indexed: 05/27/2023]
Abstract
Kinetic and structural investigations of the flavohemoglobin-type NO dioxygenase have suggested critical roles for transient Fe(III)O2 complex formation and O2-forced movements affecting hydride transfer to the FAD cofactor and electron-transfer to the Fe(III)O2 complex. Stark-effect theory together with structural models and dipole and internal electrostatic field determinations provided a semi-quantitative spectroscopic method for investigating the proposed Fe(III)O2 complex and O2-forced movements. Deoxygenation of the enzyme causes Stark effects on the ferric heme Soret and charge-transfer bands revealing the Fe(III)O2 complex. Deoxygenation also elicits Stark effects on the FAD that expose forces and motions that create a more restricted NADH access to FAD for hydride transfer and switch electron-transfer off. Glucose also forces the enzyme toward an off state. Amino acid substitutions at the B10, E7, E11, G8, D5, and F7 positions influence the Stark effects of O2 on resting heme spin states and FAD consistent with the proposed roles of the side chains in the enzyme mechanism. Deoxygenation of ferric myoglobin and hemoglobin A also induces Stark effects on the hemes suggesting a common 'oxy-met' state. The ferric myoglobin and hemoglobin heme spectra are also glucose-responsive. A conserved glucose or glucose-6-phosphate binding site is found bridging the BC-corner and G-helix in flavohemoglobin and myoglobin suggesting novel allosteric effector roles for glucose or glucose-6-phosphate in the NO dioxygenase and O2 storage functions. The results support the proposed roles of a ferric O2 intermediate and protein motions in regulating electron-transfer during NO dioxygenase turnover.
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Affiliation(s)
- Anne M Gardner
- Research and Development Division, Miami Valley Biotech, Suite 2445, 1001 E. 2(nd) Street, Dayton, OH 45402, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, R033, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
| | - Paul R Gardner
- Research and Development Division, Miami Valley Biotech, Suite 2445, 1001 E. 2(nd) Street, Dayton, OH 45402, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, R033, 3333 Burnet Avenue, Cincinnati, OH 45229, USA; Chemistry and Biochemistry Department, University of Dayton, 300 College Park, Dayton, OH 45469, USA.
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2
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Strategies of Pathogens to Escape from NO-Based Host Defense. Antioxidants (Basel) 2022; 11:antiox11112176. [DOI: 10.3390/antiox11112176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
Nitric oxide (NO) is an essential signaling molecule present in most living organisms including bacteria, fungi, plants, and animals. NO participates in a wide range of biological processes including vasomotor tone, neurotransmission, and immune response. However, NO is highly reactive and can give rise to reactive nitrogen and oxygen species that, in turn, can modify a broad range of biomolecules. Much evidence supports the critical role of NO in the virulence and replication of viruses, bacteria, protozoan, metazoan, and fungi, thus representing a general mechanism of host defense. However, pathogens have developed different mechanisms to elude the host NO and to protect themselves against oxidative and nitrosative stress. Here, the strategies evolved by viruses, bacteria, protozoan, metazoan, and fungi to escape from the NO-based host defense are overviewed.
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Chhaya A, Sharma A, Dattu Hade M, Kaur J, Dikshit KL. Transcript analysis and expression of the glbO gene, encoding truncated hemoglobin,O, of M. smegmatis implicate its role under hypoxia and oxidative stress. Gene X 2022; 841:146759. [PMID: 35933051 DOI: 10.1016/j.gene.2022.146759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Accepted: 07/24/2022] [Indexed: 12/12/2022] Open
Abstract
Although truncated hemoglobin O, (trHbO), is ubiquitous among mycobacteria, its physiological function is not very obvious and may be diverse. In an attempt to understand role of trHbO in cellular metabolism of a non-pathogenic mycobacterium, we analysed expression profile of the glbO gene, encoding trHbO, in M. smegmatis and studied implications of its overexpression on physiology of its host under different environmental conditions. Quantitative RT-PCR indicated that transcript level of the glbO gene remains low at a basal level under aerobic growth cycle of M. smegmatis but its level gets induced significantly during low oxygen, oxidative stress and macrophage infection. Overexpression of the glbO gene enhanced growth of M. smegmatis under hypoxia, promoted pellicle biofilm formation and provided resistance towards oxidative stress. Additionally, glbO gene overexpressing M. smegmatis exhibited enhanced cell survival over isogenic control cells and altered the level of pro- and anti- inflammatory cytokines during intracellular infection. These results suggested important role of trHbO, in supporting the cellular metabolism and survival of M, smegmatis both under low oxygen and oxidative stress.
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Affiliation(s)
- Ajay Chhaya
- Department of Biotechnology, Panjab University, Chandigarh 160014, India
| | - Aashish Sharma
- Department of Biotechnology, Panjab University, Chandigarh 160014, India
| | - Mangesh Dattu Hade
- Department of Biotechnology, Panjab University, Chandigarh 160014, India
| | - Jagdeep Kaur
- Department of Biotechnology, Panjab University, Chandigarh 160014, India
| | - Kanak L Dikshit
- Department of Biotechnology, Panjab University, Chandigarh 160014, India.
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Defenses of multidrug resistant pathogens against reactive nitrogen species produced in infected hosts. Adv Microb Physiol 2022; 80:85-155. [PMID: 35489794 DOI: 10.1016/bs.ampbs.2022.02.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Bacterial pathogens have sophisticated systems that allow them to survive in hosts in which innate immunity is the frontline of defense. One of the substances produced by infected hosts is nitric oxide (NO) that together with its derived species leads to the so-called nitrosative stress, which has antimicrobial properties. In this review, we summarize the current knowledge on targets and protective systems that bacteria have to survive host-generated nitrosative stress. We focus on bacterial pathogens that pose serious health concerns due to the growing increase in resistance to currently available antimicrobials. We describe the role of nitrosative stress as a weapon for pathogen eradication, the detoxification enzymes, protein/DNA repair systems and metabolic strategies that contribute to limiting NO damage and ultimately allow survival of the pathogen in the host. Additionally, this systematization highlights the lack of available data for some of the most important human pathogens, a gap that urgently needs to be addressed.
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Thakur N, Sharma AN, Hade MD, Chhaya A, Kumar A, Jolly RS, Dikshit KL. New Insights Into the Function of Flavohemoglobin in Mycobacterium tuberculosis: Role as a NADPH-Dependent Disulfide Reductase and D-Lactate-Dependent Mycothione Reductase. Front Cell Infect Microbiol 2022; 11:796727. [PMID: 35237528 PMCID: PMC8883573 DOI: 10.3389/fcimb.2021.796727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 12/31/2021] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) produces an unconventional flavohemoglobin (MtbFHb) that carries a FAD-binding site similar to D-lactate dehydrogenases (D-LDH) and oxidizes D-lactate into pyruvate. The molecular mechanism by which MtbFHb functions in Mtb remains unknown. We discovered that the D-LDH-type FAD-binding site in MtbFHb overlaps with another FAD-binding motif similar to thioredoxin reductases and reduces DTNB in the presence of NADPH similar to trxB of Mtb. These results suggested that MtbFHb is functioning as a disulfide oxidoreductase. Interestingly, D-lactate created a conformational change in MtbFHb and attenuated its ability to oxidize NADPH. Mass spectroscopy demonstrated that MtbFHb reduces des-myo-inositol mycothiol in the presence of D-lactate unlike NADPH, indicating that D-lactate changes the specificity of MtbFHb from di-thiol to di-mycothiol. When M. smegmatis carrying deletion in the fhbII gene (encoding a homolog of MtbFHb) was complemented with the fhb gene of Mtb, it exhibited four- to fivefold reductions in lipid peroxidation and significant enhancement in the cell survival under oxidative stress. These results were corroborated by reduced lipid peroxidation and enhanced cell survival of wild-type M. smegmatis after overexpression of the fhb gene of Mtb. Since D-lactate is a by-product of lipid peroxidation and MtbFHb is a membrane-associated protein, D-lactate-mediated reduction of mycothiol disulfide by MtbFHb may uniquely equip Mtb to relieve the toxicity of D-lactate accumulation and protect the cell from oxidative damage, simultaneously balancing the redox environment under oxidative stress that may be vital for the pathogenesis of Mtb.
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Affiliation(s)
- Naveen Thakur
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | | | | | - Ajay Chhaya
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Ashwani Kumar
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | | | - Kanak L. Dikshit
- CSIR-Institute of Microbial Technology, Chandigarh, India
- Department of Biotechnology, Panjab University, Chandigarh, India
- *Correspondence: Kanak L. Dikshit,
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Gardner PR. Ordered Motions in the Nitric-Oxide Dioxygenase Mechanism of Flavohemoglobin and Assorted Globins with Tightly Coupled Reductases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1414:45-96. [PMID: 36520413 DOI: 10.1007/5584_2022_751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Nitric-oxide dioxygenases (NODs) activate and combine O2 with NO to form nitrate. A variety of oxygen-binding hemoglobins with associated partner reductases or electron donors function as enzymatic NODs. Kinetic and structural investigations of the archetypal two-domain microbial flavohemoglobin-NOD have illuminated an allosteric mechanism that employs selective tunnels for O2 and NO, gates for NO and nitrate, transient O2 association with ferric heme, and an O2 and NO-triggered, ferric heme spin crossover-driven, motion-controlled, and dipole-regulated electron-transfer switch. The proposed mechanism facilitates radical-radical coupling of ferric-superoxide with NO to form nitrate while preventing suicidal ferrous-NO formation. Diverse globins display the structural and functional motifs necessary for a similar allosteric NOD mechanism. In silico docking simulations reveal monomeric erythrocyte hemoglobin alpha-chain and beta-chain intrinsically matched and tightly coupled with NADH-cytochrome b5 oxidoreductase and NADPH-cytochrome P450 oxidoreductase, respectively, forming membrane-bound flavohemoglobin-like mammalian NODs. The neuroprotective neuroglobin manifests a potential NOD role in a close-fitting ternary complex with membrane-bound NADH-cytochrome b5 oxidoreductase and cytochrome b5. Cytoglobin interfaces weakly with cytochrome b5 for O2 and NO-regulated electron-transfer and coupled NOD activity. The mechanistic model also provides insight into the evolution of O2 binding cooperativity in hemoglobin and a basis for the discovery of allosteric NOD inhibitors.
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Nardini M, Pesce A, Bolognesi M. Truncated (2/2) hemoglobin: Unconventional structures and functional roles in vivo and in human pathogenesis. Mol Aspects Med 2021; 84:101049. [PMID: 34776271 DOI: 10.1016/j.mam.2021.101049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022]
Abstract
Truncated hemoglobins (trHbs) build a sub-class of the globin family, found in eubacteria, cyanobacteria, unicellular eukaryotes, and in higher plants; among these, selected human pathogens are found. The trHb fold is based on a 2/2 α-helical sandwich, consisting of a simplified and reduced-size version of the classical 3/3 α-helical sandwich of vertebrate and invertebrate globins. Phylogenetic analysis indicates that trHbs further branch into three groups: group I (or trHbN), group II (or trHbO), and group III (or trHbP), each group being characterized by specific structural features. Among these, a protein matrix tunnel, or a cavity system implicated in diatomic ligand diffusion through the protein matrix, is typical of group I and group II, respectively. In general, a highly intertwined network of hydrogen bonds stabilizes the heme bound ligand, despite variability of the heme distal residues in the different trHb groups. Notably, some organisms display genes from more than one trHb group, suggesting that trHbN, trHbO, and trHbP may support different functions in vivo, such as detoxification of reactive nitrogen and oxygen species, respiration, oxygen storage/sensoring, thus aiding survival of an invading microorganism. Here, structural features and proposed functions of trHbs from human pathogens are reviewed.
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Affiliation(s)
- Marco Nardini
- Department of Biosciences, University of Milano, Milano, Italy
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Abukhalid N, Islam S, Ndzeidze R, Bermudez LE. Mycobacterium avium Subsp. hominissuis Interactions with Macrophage Killing Mechanisms. Pathogens 2021; 10:pathogens10111365. [PMID: 34832521 PMCID: PMC8623537 DOI: 10.3390/pathogens10111365] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 09/30/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022] Open
Abstract
Non-tuberculosis mycobacteria (NTM) are ubiquitously found throughout the environment. NTM can cause respiratory infections in individuals with underlying lung conditions when inhaled, or systemic infections when ingested by patients with impaired immune systems. Current therapies can be ineffective at treating NTM respiratory infections, even after a long course or with multidrug treatment regimens. NTM, such as Mycobacterium avium subspecies hominissuis (M. avium), is an opportunistic pathogen that shares environments with ubiquitous free-living amoeba and other environmental hosts, possibly their evolutionary hosts. It is highly likely that interactions between M. avium and free-living amoeba have provided selective pressure on the bacteria to acquire survival mechanisms, which are also used against predation by macrophages. In macrophages, M. avium resides inside phagosomes and has been shown to exit it to infect other cells. M. avium’s adaptation to the hostile intra-phagosomal environment is due to many virulence mechanisms. M. avium is able to switch the phenotype of the macrophage to be anti-inflammatory (M2). Here, we have focused on and discussed the bacterial defense mechanisms associated with the intra-phagosome phase of infection. M. avium possesses a plethora of antioxidant enzymes, including the superoxide dismutases, catalase and alkyl hydroperoxide reductase. When these defenses fail or are overtaken by robust oxidative burst, many other enzymes exist to repair damage incurred on M. avium proteins, including thioredoxin/thioredoxin reductase. Finally, M. avium has several oxidant sensors that induce transcription of antioxidant enzymes, oxidation repair enzymes and biofilm- promoting genes. These expressions induce physiological changes that allow M. avium to survive in the face of leukocyte-generated oxidative stress. We will discuss the strategies used by M. avium to infect human macrophages that evolved during its evolution from free-living amoeba. The more insight we gain about M. avium’s mode of pathogenicity, the more targets we can have to direct new anti-virulence therapies toward.
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Affiliation(s)
- Norah Abukhalid
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; (N.A.); (S.I.); (R.N.)
| | - Sabrina Islam
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; (N.A.); (S.I.); (R.N.)
| | - Robert Ndzeidze
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; (N.A.); (S.I.); (R.N.)
| | - Luiz E. Bermudez
- Department of Biomedical Sciences, College of Veterinary Medicine, Oregon State University, Corvallis, OR 97331, USA; (N.A.); (S.I.); (R.N.)
- Department of Microbiology, College of Science, Oregon State University, Corvallis, OR 97331, USA
- Correspondence:
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Salas A, Cabrera JJ, Jiménez-Leiva A, Mesa S, Bedmar EJ, Richardson DJ, Gates AJ, Delgado MJ. Bacterial nitric oxide metabolism: Recent insights in rhizobia. Adv Microb Physiol 2021; 78:259-315. [PMID: 34147187 DOI: 10.1016/bs.ampbs.2021.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Nitric oxide (NO) is a reactive gaseous molecule that has several functions in biological systems depending on its concentration. At low concentrations, NO acts as a signaling molecule, while at high concentrations, it becomes very toxic due to its ability to react with multiple cellular targets. Soil bacteria, commonly known as rhizobia, have the capacity to establish a N2-fixing symbiosis with legumes inducing the formation of nodules in their roots. Several reports have shown NO production in the nodules where this gas acts either as a signaling molecule which regulates gene expression, or as a potent inhibitor of nitrogenase and other plant and bacteria enzymes. A better understanding of the sinks and sources of NO in rhizobia is essential to protect symbiotic nitrogen fixation from nitrosative stress. In nodules, both the plant and the microsymbiont contribute to the production of NO. From the bacterial perspective, the main source of NO reported in rhizobia is the denitrification pathway that varies significantly depending on the species. In addition to denitrification, nitrate assimilation is emerging as a new source of NO in rhizobia. To control NO accumulation in the nodules, in addition to plant haemoglobins, bacteroids also contribute to NO detoxification through the expression of a NorBC-type nitric oxide reductase as well as rhizobial haemoglobins. In the present review, updated knowledge about the NO metabolism in legume-associated endosymbiotic bacteria is summarized.
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Affiliation(s)
- Ana Salas
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Juan J Cabrera
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain; School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Andrea Jiménez-Leiva
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Socorro Mesa
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - Eulogio J Bedmar
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain
| | - David J Richardson
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Andrew J Gates
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - María J Delgado
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas, Granada, Spain.
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Porrini C, Ramarao N, Tran SL. Dr. NO and Mr. Toxic - the versatile role of nitric oxide. Biol Chem 2021; 401:547-572. [PMID: 31811798 DOI: 10.1515/hsz-2019-0368] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 12/04/2019] [Indexed: 12/25/2022]
Abstract
Nitric oxide (NO) is present in various organisms from humans, to plants, fungus and bacteria. NO is a fundamental signaling molecule implicated in major cellular functions. The role of NO ranges from an essential molecule to a potent mediator of cellular damages. The ability of NO to react with a broad range of biomolecules allows on one hand its regulation and a gradient concentration and on the other hand to exert physiological as well as pathological functions. In humans, NO is implicated in cardiovascular homeostasis, neurotransmission and immunity. However, NO can also contribute to cardiovascular diseases (CVDs) or septic shock. For certain denitrifying bacteria, NO is part of their metabolism as a required intermediate of the nitrogen cycle. However, for other bacteria, NO is toxic and harmful. To survive, those bacteria have developed processes to resist this toxic effect and persist inside their host. NO also contributes to maintain the host/microbiota homeostasis. But little is known about the impact of NO produced during prolonged inflammation on microbiota integrity, and some pathogenic bacteria take advantage of the NO response to colonize the gut over the microbiota. Taken together, depending on the environmental context (prolonged production, gradient concentration, presence of partners for interaction, presence of oxygen, etc.), NO will exert its beneficial or detrimental function. In this review, we highlight the dual role of NO for humans, pathogenic bacteria and microbiota, and the mechanisms used by each organism to produce, use or resist NO.
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Affiliation(s)
- Constance Porrini
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Nalini Ramarao
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
| | - Seav-Ly Tran
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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Gardner AM, Gardner PR. Allostery in the nitric oxide dioxygenase mechanism of flavohemoglobin. J Biol Chem 2020; 296:100186. [PMID: 33310705 PMCID: PMC7948479 DOI: 10.1074/jbc.ra120.016637] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/09/2020] [Accepted: 12/11/2020] [Indexed: 12/12/2022] Open
Abstract
The substrates O2 and NO cooperatively activate the NO dioxygenase function of Escherichia coli flavohemoglobin. Steady-state and transient kinetic measurements support a structure-based mechanistic model in which O2 and NO movements and conserved amino acids at the E11, G8, E2, E7, B10, and F7 positions within the globin domain control activation. In the cooperative and allosteric mechanism, O2 migrates to the catalytic heme site via a long hydrophobic tunnel and displaces LeuE11 away from the ferric iron, which forces open a short tunnel to the catalytic site gated by the ValG8/IleE15 pair and LeuE11. NO permeates this tunnel and leverages upon the gating side chains triggering the CD loop to furl, which moves the E and F-helices and switches an electron transfer gate formed by LysF7, GlnE7, and water. This allows FADH2 to reduce the ferric iron, which forms the stable ferric–superoxide–TyrB10/GlnE7 complex. This complex reacts with internalized NO with a bimolecular rate constant of 1010 M−1 s−1 forming nitrate, which migrates to the CD loop and unfurls the spring-like structure. To restart the cycle, LeuE11 toggles back to the ferric iron. Actuating electron transfer with O2 and NO movements averts irreversible NO poisoning and reductive inactivation of the enzyme. Together, structure snapshots and kinetic constants provide glimpses of intermediate conformational states, time scales for motion, and associated energies.
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Affiliation(s)
- Anne M Gardner
- Research and Development Division, Miami Valley Biotech, Dayton, Ohio, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA
| | - Paul R Gardner
- Research and Development Division, Miami Valley Biotech, Dayton, Ohio, USA; Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA; Chemistry and Biochemistry Department, University of Dayton, Dayton, Ohio, USA.
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12
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Nitric Oxide Does Not Inhibit but Is Metabolized by the Cytochrome bcc- aa3 Supercomplex. Int J Mol Sci 2020; 21:ijms21228521. [PMID: 33198276 PMCID: PMC7697965 DOI: 10.3390/ijms21228521] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/08/2020] [Accepted: 11/10/2020] [Indexed: 12/12/2022] Open
Abstract
Nitric oxide (NO) is a well-known active site ligand and inhibitor of respiratory terminal oxidases. Here, we investigated the interaction of NO with a purified chimeric bcc-aa3 supercomplex composed of Mycobacterium tuberculosis cytochrome bcc and Mycobacterium smegmatisaa3-type terminal oxidase. Strikingly, we found that the enzyme in turnover with O2 and reductants is resistant to inhibition by the ligand, being able to metabolize NO at 25 °C with an apparent turnover number as high as ≈303 mol NO (mol enzyme)−1 min−1 at 30 µM NO. The rate of NO consumption proved to be proportional to that of O2 consumption, with 2.65 ± 0.19 molecules of NO being consumed per O2 molecule by the mycobacterial bcc-aa3. The enzyme was found to metabolize the ligand even under anaerobic reducing conditions with a turnover number of 2.8 ± 0.5 mol NO (mol enzyme)−1 min−1 at 25 °C and 8.4 µM NO. These results suggest a protective role of mycobacterial bcc-aa3 supercomplexes against NO stress.
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13
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Hade MD, Sethi D, Datta H, Singh S, Thakur N, Chhaya A, Dikshit KL. Truncated Hemoglobin O Carries an Autokinase Activity and Facilitates Adaptation of Mycobacterium tuberculosis Under Hypoxia. Antioxid Redox Signal 2020; 32:351-362. [PMID: 31218881 DOI: 10.1089/ars.2018.7708] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Aims: Although the human pathogen, Mycobacterium tuberculosis (Mtb), is strictly aerobic and requires efficient supply of oxygen, it can survive long stretches of severe hypoxia. The mechanism responsible for this metabolic flexibility is unknown. We have investigated a novel mechanism by which hemoglobin O (HbO), operates and supports its host under oxygen stress. Results: We discovered that the HbO exists in a phospho-bound state in Mtb and remains associated with the cell membrane under hypoxia. Deoxy-HbO carries an autokinase activity that disrupts its dimeric assembly into monomer and facilitates its association with the cell membrane, supporting survival and adaptation of Mtb under low oxygen conditions. Consistent with these observations, deletion of the glbO gene in Mycobacterium bovis bacillus Calmette-Guerin, which is identical to the glbO gene of Mtb, attenuated its survival under hypoxia and complementation of the glbO gene of Mtb rescued this inhibition, but phosphorylation-deficient mutant did not. These results demonstrated that autokinase activity of the HbO modulates its physiological function and plays a vital role in supporting the survival of its host under hypoxia. Innovation and Conclusion: Our study demonstrates that the redox-dependent autokinase activity regulates oligomeric state and membrane association of HbO that generates a reservoir of oxygen in the proximity of respiratory membranes to sustain viability of Mtb under hypoxia. These results thus provide a novel insight into the physiological function of the HbO and demonstrate its pivotal role in supporting the survival and adaptation of Mtb under hypoxia.
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Affiliation(s)
| | - Deepti Sethi
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Himani Datta
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sandeep Singh
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Naveen Thakur
- CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Ajay Chhaya
- Department of Biotechnology, Panjab University, Chandigarh, India
| | - Kanak L Dikshit
- CSIR-Institute of Microbial Technology, Chandigarh, India.,Department of Biotechnology, Panjab University, Chandigarh, India
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Boubeta FM, Boechi L, Estrin D, Patrizi B, Di Donato M, Iagatti A, Giordano D, Verde C, Bruno S, Abbruzzetti S, Viappiani C. Cold-Adaptation Signatures in the Ligand Rebinding Kinetics to the Truncated Hemoglobin of the Antarctic Bacterium Pseudoalteromonas haloplanktis TAC125. J Phys Chem B 2018; 122:11649-11661. [PMID: 30230844 DOI: 10.1021/acs.jpcb.8b07682] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Cold-adapted organisms have evolved proteins endowed with higher flexibility and lower stability in comparison to their thermophilic homologues, resulting in enhanced reaction rates at low temperatures. In this context, protein-bound water molecules were suggested to play a major role, and their weaker interactions at protein active sites have been associated with cold adaptation. In this work, we tested this hypothesis on truncated hemoglobins (a family of microbial heme-proteins of yet-unclear function) applying molecular dynamics simulations and ligand-rebinding kinetics on a protein from the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125 in comparison with its thermophilic Thermobifida fusca homologue. The CO rebinding kinetics of the former highlight several geminate phases, with an unusually long-lived geminate intermediate. An articulated tunnel with at least two distinct docking sites was identified by analysis of molecular dynamics simulations and was suggested to be at the origin of the unusual geminate rebinding phase. Water molecules are present in the distal pocket, but their stabilization by TrpG8, TyrB10, and HisCD1 is much weaker than in thermophilic Thermobifida fusca truncated hemoglobin, resulting in a faster geminate rebinding. Our results support the hypothesis that weaker water-molecule interactions at the reaction site are associated with cold adaptation.
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Affiliation(s)
- Fernando M Boubeta
- Instituto de Quimica Fisica de los Materiales, Medio Ambiente y Energia (INQUIMAE), CONICET, and Universidad de Buenos Aires , C1428EHA Buenos Aires , Argentina
| | - Leonardo Boechi
- Instituto de Calculo, Facultad de Ciencias Exactas y Naturales , Universidad de Buenos Aires , C1428EGA Buenos Aires , Argentina
| | - Dario Estrin
- Instituto de Quimica Fisica de los Materiales, Medio Ambiente y Energia (INQUIMAE), CONICET, and Universidad de Buenos Aires , C1428EHA Buenos Aires , Argentina
| | - Barbara Patrizi
- European Laboratory for Non Linear Spectroscopy (LENS), Università di Firenze , Via Nello Carrara 1 , 50019 Sesto Fiorentino, Florence , Italy.,INO-CNR, Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche , Largo Fermi 6 , 50125 Florence , Italy
| | - Mariangela Di Donato
- European Laboratory for Non Linear Spectroscopy (LENS), Università di Firenze , Via Nello Carrara 1 , 50019 Sesto Fiorentino, Florence , Italy.,INO-CNR, Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche , Largo Fermi 6 , 50125 Florence , Italy
| | - Alessandro Iagatti
- European Laboratory for Non Linear Spectroscopy (LENS), Università di Firenze , Via Nello Carrara 1 , 50019 Sesto Fiorentino, Florence , Italy
| | - Daniela Giordano
- Institute of Biosciences and BioResources (IBBR), CNR , Via Pietro Castellino 111 , I-80131 Naples , Italy.,Stazione Zoologica Anton Dohrn , Villa Comunale , 80121 Naples , Italy
| | - Cinzia Verde
- Institute of Biosciences and BioResources (IBBR), CNR , Via Pietro Castellino 111 , I-80131 Naples , Italy.,Stazione Zoologica Anton Dohrn , Villa Comunale , 80121 Naples , Italy
| | - Stefano Bruno
- Dipartimento di Scienze degli Alimenti e del Farmaco , Università di Parma , Parco Area delle Scienze 23A , 43124 , Parma , Italy
| | - Stefania Abbruzzetti
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche , Università di Parma , Parco Area delle Scienze 7A , 43124 , Parma , Italy
| | - Cristiano Viappiani
- Dipartimento di Scienze Matematiche, Fisiche e Informatiche , Università di Parma , Parco Area delle Scienze 7A , 43124 , Parma , Italy
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15
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Chawla M, Mishra S, Anand K, Parikh P, Mehta M, Vij M, Verma T, Singh P, Jakkala K, Verma HN, AjitKumar P, Ganguli M, Narain Seshasayee AS, Singh A. Redox-dependent condensation of the mycobacterial nucleoid by WhiB4. Redox Biol 2018; 19:116-133. [PMID: 30149290 PMCID: PMC6111044 DOI: 10.1016/j.redox.2018.08.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 08/02/2018] [Accepted: 08/11/2018] [Indexed: 12/22/2022] Open
Abstract
Oxidative stress response in bacteria is mediated through coordination between the regulators of oxidant-remediation systems (e.g. OxyR, SoxR) and nucleoid condensation (e.g. Dps, Fis). However, these genetic factors are either absent or rendered non-functional in the human pathogen Mycobacterium tuberculosis (Mtb). Therefore, how Mtb organizes genome architecture and regulates gene expression to counterbalance oxidative imbalance is unknown. Here, we report that an intracellular redox-sensor, WhiB4, dynamically links genome condensation and oxidative stress response in Mtb. Disruption of WhiB4 affects the expression of genes involved in maintaining redox homeostasis, central metabolism, and respiration under oxidative stress. Notably, disulfide-linked oligomerization of WhiB4 in response to oxidative stress activates the protein’s ability to condense DNA. Further, overexpression of WhiB4 led to hypercondensation of nucleoids, redox imbalance and increased susceptibility to oxidative stress, whereas WhiB4 disruption reversed this effect. In accordance with the findings in vitro, ChIP-Seq data demonstrated non-specific binding of WhiB4 to GC-rich regions of the Mtb genome. Lastly, data indicate that WhiB4 deletion affected the expression of ~ 30% of genes preferentially bound by the protein, suggesting both direct and indirect effects on gene expression. We propose that WhiB4 structurally couples Mtb’s response to oxidative stress with genome organization and transcription. Genome condensation is involved in the management of oxidative stress in bacteria. A relation between the genome condensation and oxidative stress is unclear in Mtb. A redox sensor WhiB4 calibrates genome-condensation and antioxidants in Mtb. Over-expression of WhiB4 hyper-condensed genome and induced killing by oxidants. WhiB4 deficiency delayed genome condensation and promoted oxidative stress survival.
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Affiliation(s)
- Manbeena Chawla
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Saurabh Mishra
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Kushi Anand
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Pankti Parikh
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Mansi Mehta
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Manika Vij
- Department of Structural Biology, CSIR-Institute of Genomics and Integrative Biology, South Campus, Mathura Road, New Delhi 110020, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | - Taru Verma
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India; Centre for BioSystems Science and Engineering (BSSE), Indian Institute of Science, Bangalore 560012, India
| | - Parul Singh
- National Centre for Biological Science, Bangalore 560065, India; SASTRA University, Thanjavur 613401, Tamil Nadu, India
| | - Kishor Jakkala
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - H N Verma
- Jaipur National University, Jagatpura, Jaipur 302017, India
| | - Parthasarathi AjitKumar
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India
| | - Munia Ganguli
- Department of Structural Biology, CSIR-Institute of Genomics and Integrative Biology, South Campus, Mathura Road, New Delhi 110020, India; Academy of Scientific and Innovative Research (AcSIR), Anusandhan Bhawan, 2 Rafi Marg, New Delhi 110001, India
| | | | - Amit Singh
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore 560012, India.
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16
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Pahari S, Kaur G, Negi S, Aqdas M, Das DK, Bashir H, Singh S, Nagare M, Khan J, Agrewala JN. Reinforcing the Functionality of Mononuclear Phagocyte System to Control Tuberculosis. Front Immunol 2018; 9:193. [PMID: 29479353 PMCID: PMC5811511 DOI: 10.3389/fimmu.2018.00193] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/23/2018] [Indexed: 12/12/2022] Open
Abstract
The mononuclear phagocyte system (MPS) constitutes dendritic cells, monocytes, and macrophages. This system contributes to various functions that are essential for maintaining homeostasis, activation of innate immunity, and bridging it with the adaptive immunity. Consequently, MPS is highly important in bolstering immunity against the pathogens. However, MPS is the frontline cells in destroying Mycobacterium tuberculosis (Mtb), yet the bacterium prefers to reside in the hostile environment of macrophages. Therefore, it may be very interesting to study the struggle between Mtb and MPS to understand the outcome of the disease. In an event when MPS predominates Mtb, the host remains protected. By contrast, the situation becomes devastating when the pathogen tames and tunes the host MPS, which ultimately culminates into tuberculosis (TB). Hence, it becomes extremely crucial to reinvigorate MPS functionality to overwhelm Mtb and eliminate it. In this article, we discuss the strategies to bolster the function of MPS by exploiting the molecules associated with the innate immunity and highlight the mechanisms involved to overcome the Mtb-induced suppression of host immunity. In future, such approaches may provide an insight to develop immunotherapeutics to treat TB.
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Affiliation(s)
- Susanta Pahari
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Gurpreet Kaur
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Shikha Negi
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Mohammad Aqdas
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Deepjyoti K Das
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Hilal Bashir
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Sanpreet Singh
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Mukta Nagare
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Junaid Khan
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
| | - Javed N Agrewala
- Immunology Laboratory, CSIR-Institute of Microbial Technology, Chandigarh, India
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17
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Thakur N, Kumar A, Dikshit KL. Type II flavohemoglobin of Mycobacterium smegmatis oxidizes d-lactate and mediate electron transfer. Int J Biol Macromol 2018; 112:868-875. [PMID: 29428388 DOI: 10.1016/j.ijbiomac.2018.02.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Revised: 01/29/2018] [Accepted: 02/02/2018] [Indexed: 12/12/2022]
Abstract
Two distantly related flavohemoglobins (FHbs), MsFHbI and MsFHbII, having crucial differences in their heme and reductase domains, co-exist in Mycobacterium smegmatis. Function of MsFHbI is associated with nitric-oxide detoxification but physiological relevance of MsFHbII remains unknown. This study unravels some unique spectral and functional characteristics of MsFHbII. Unlike conventional type I FHbs, MsFHbII lacks nitric-oxide dioxygenase and NADH oxidase activities but utilizes d-lactate as an electron donor to mediate electron transfer. MsFHbII carries a d-lactate dehydrogenase type FAD binding motif in its reductase domain and oxidizes d-lactate in a FAD dependent manner to reduce the heme iron, suggesting that the globin is acting as an electron acceptor. Importantly, expression of MsFHbII in Escherichia coli imparted protection under oxidative stress, suggesting its important role in stress management of its host. Since M. smegmatis lacks the gene encoding for d-lactate dehydrogenase and d-lactate is produced during aerobic metabolism and also as a by-product of lipid peroxidation, the ability of MsFHbII to metabolize d-lactate may provide it a unique ability to balance the oxidative stress generated due to accumulation of d-lactate in the cell and at the same time sequester electrons and pass it to the respiratory apparatus.
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Affiliation(s)
- Naveen Thakur
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, India
| | - Ashwani Kumar
- CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh, India
| | - Kanak L Dikshit
- Department of Biotechnology, Panjab University, Sector 25, South Block, Chandigarh, India.
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18
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Sousa EHS, Gonzalez G, Gilles-Gonzalez MA. Target DNA stabilizes Mycobacterium tuberculosis DevR/DosR phosphorylation by the full-length oxygen sensors DevS/DosS and DosT. FEBS J 2017; 284:3954-3967. [PMID: 28977726 DOI: 10.1111/febs.14284] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/14/2017] [Accepted: 09/29/2017] [Indexed: 12/13/2022]
Abstract
Mycobacterium tuberculosis strongly relies on a latency, or nonreplicating persistence, to escape a human host's immune system. The DevR (DosR), DevS (DosS), and DosT proteins are key components of this process. Like the rhizobial FixL oxygen sensor, DevS and DosT are histidine protein kinases with a heme-binding domain. Like the FixJ partner and substrate of FixL, DevR is a classical response regulator of the two-component class. When activated by DevS or DosT during hypoxia in vivo, DevR induces a dormancy regulon of more than 40 genes. To investigate the contributions of DevS, DosT, and target DNA to the phosphorylation of DevR, we developed an in vitro assay in which the full-length, sensing, DevS and DosT proteins were used to phosphorylate DevR with ATP, in the presence of target DNAs that were introduced as oligonucleotides linked to magnetic nanoparticles. We found that the DevR phosphorylations proceeded only for the deoxy states of the sensors. The reaction was strongly inhibited by O2 , but not CO or NO. The production of phospho-DevR was enhanced sixfold by target consensus DNA or acr-DNA. The phospho-DevR bound tightly to that DNA (Kd ~ 0.8 nm toward acr-DNA), and it was only slightly displaced by a 200-fold excess of unphosphorylated DevR or of a truncated DevR with only a DNA-binding domain. To our knowledge, this represents the first in vitro study of the ligand regulation of DevR phosphorylation by full-length DevS and DosT, and demonstration of a positive effect of DNA on this reaction.
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Affiliation(s)
- Eduardo H S Sousa
- Laboratory of Bioinorganic Chemistry, Department of Organic and Inorganic Chemistry, Federal University of Ceara, Center for Sciences, Fortaleza, Brazil
| | - Gonzalo Gonzalez
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
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19
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Preimesberger MR, Johnson EA, Nye DB, Lecomte JTJ. Covalent attachment of the heme to Synechococcus hemoglobin alters its reactivity toward nitric oxide. J Inorg Biochem 2017; 177:171-182. [PMID: 28968520 DOI: 10.1016/j.jinorgbio.2017.09.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 01/19/2023]
Abstract
The cyanobacterium Synechococcus sp. PCC 7002 produces a monomeric hemoglobin (GlbN) implicated in the detoxification of reactive nitrogen and oxygen species. GlbN contains a b heme, which can be modified under certain reducing conditions. The modified protein (GlbN-A) has one heme-histidine C-N linkage similar to the C-S linkage of cytochrome c. No clear functional role has been assigned to this modification. Here, optical absorbance and NMR spectroscopies were used to compare the reactivity of GlbN and GlbN-A toward nitric oxide (NO). Both forms of the protein are capable of NO dioxygenase activity and both undergo heme bleaching after multiple NO challenges. GlbN and GlbN-A bind NO in the ferric state and form diamagnetic complexes (FeIII-NO) that resist reductive nitrosylation to the paramagnetic FeII-NO forms. Dithionite reduction of FeIII-NO GlbN and GlbN-A, however, resulted in distinct outcomes. Whereas GlbN-A rapidly formed the expected FeII-NO complex, NO binding to FeII GlbN caused immediate heme loss and, remarkably, was followed by slow heme rebinding and HNO (nitrosyl hydride) production. Additionally, combining FeIII GlbN, 15N-labeled nitrite, and excess dithionite resulted in the formation of FeII-H15NO GlbN. Dithionite-mediated HNO production was also observed for the related GlbN from Synechocystis sp. PCC 6803. Although ferrous GlbN-A appeared capable of trapping preformed HNO, the histidine-heme post-translational modification extinguished the NO reduction chemistry associated with GlbN. Overall, the results suggest a role for the covalent modification in FeII GlbNs: protection from NO-mediated heme loss and prevention of HNO formation.
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Affiliation(s)
| | - Eric A Johnson
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Dillon B Nye
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Juliette T J Lecomte
- T.C. Jenkins Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA.
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20
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Nitrosative stress defences of the enterohepatic pathogenic bacterium Helicobacter pullorum. Sci Rep 2017; 7:9909. [PMID: 28855660 PMCID: PMC5577044 DOI: 10.1038/s41598-017-10375-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 08/07/2017] [Indexed: 01/28/2023] Open
Abstract
Helicobacter pullorum is an avian bacterium that causes gastroenteritis, intestinal bowel and hepatobiliary diseases in humans. Although H. pullorum has been shown to activate the mammalian innate immunity with release of nitric oxide (NO), the proteins that afford protection against NO and reactive nitrogen species (RNS) remain unknown. Here several protein candidates of H. pullorum, namely a truncated (TrHb) and a single domain haemoglobin (SdHb), and three peroxiredoxin-like proteins (Prx1, Prx2 and Prx3) were investigated. We report that the two haemoglobin genes are induced by RNS, and that SdHb confers resistance to nitrosative stress both in vitro and in macrophages. For peroxiredoxins, the prx2 and prx3 expression is enhanced by peroxynitrite and hydrogen peroxide, respectively. Mutation of prx1 does not alter the resistance to these stresses, while the single ∆prx2 and double ∆prx1∆prx2 mutants have decreased viability. To corroborate the physiological data, the biochemical analysis of the five recombinant enzymes was done, namely by stopped-flow spectrophotometry. It is shown that H. pullorum SdHb reacts with NO much more quickly than TrHb, and that the three Prxs react promptly with peroxynitrite, Prx3 displaying the highest reactivity. Altogether, the results unveil SdHb and Prx3 as major protective systems of H. pullorum against nitrosative stress.
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21
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Mishra S, Shukla P, Bhaskar A, Anand K, Baloni P, Jha RK, Mohan A, Rajmani RS, Nagaraja V, Chandra N, Singh A. Efficacy of β-lactam/β-lactamase inhibitor combination is linked to WhiB4-mediated changes in redox physiology of Mycobacterium tuberculosis. eLife 2017; 6:e25624. [PMID: 28548640 PMCID: PMC5473688 DOI: 10.7554/elife.25624] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 05/24/2017] [Indexed: 12/15/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) expresses a broad-spectrum β-lactamase (BlaC) that mediates resistance to one of the highly effective antibacterials, β-lactams. Nonetheless, β-lactams showed mycobactericidal activity in combination with β-lactamase inhibitor, clavulanate (Clav). However, the mechanistic aspects of how Mtb responds to β-lactams such as Amoxicillin in combination with Clav (referred as Augmentin [AG]) are not clear. Here, we identified cytoplasmic redox potential and intracellular redox sensor, WhiB4, as key determinants of mycobacterial resistance against AG. Using computer-based, biochemical, redox-biosensor, and genetic strategies, we uncovered a functional linkage between specific determinants of β-lactam resistance (e.g. β-lactamase) and redox potential in Mtb. We also describe the role of WhiB4 in coordinating the activity of β-lactamase in a redox-dependent manner to tolerate AG. Disruption of WhiB4 enhances AG tolerance, whereas overexpression potentiates AG activity against drug-resistant Mtb. Our findings suggest that AG can be exploited to diminish drug-resistance in Mtb through redox-based interventions.
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Affiliation(s)
- Saurabh Mishra
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
| | - Prashant Shukla
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
- International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | | | - Kushi Anand
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
| | - Priyanka Baloni
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India
| | - Rajiv Kumar Jha
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
| | - Abhilash Mohan
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Raju S Rajmani
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
| | - Valakunja Nagaraja
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Nagasuma Chandra
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Amit Singh
- Microbiology and Cell Biology, Centre for Infectious Disease Research, Indian Institute of Science, Bangalore, India
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22
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Hade MD, Kaur J, Chakraborti PK, Dikshit KL. Multidomain truncated hemoglobins: New members of the globin family exhibiting tandem repeats of globin units and domain fusion. IUBMB Life 2017; 69:479-488. [PMID: 28394017 DOI: 10.1002/iub.1630] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 03/16/2017] [Indexed: 12/12/2022]
Abstract
Truncated hemoglobins (trHbs) are considered the most primitive members of globin superfamily and traditionally exist as a single domain heme protein in three distinct structural organizations, type I (trHb1_N), type II (trHb2_O) and type III (trHb3_P). Our search of microbial and lower eukaryotic genomes revealed a broad array of multidomain organization, representing multiunit and chimeric forms of trHbs, where multiple units of trHbs are joined together and/or integrated with distinct functional domains. Globin motifs of these multidomain trHbs were from all three groups of trHbs and unambiguously assigned to trHb1_N, trHb2_O and trHb3_P. Multiunit and chimeric forms of trHb1_N were identified exclusively in ciliated protozoan parasites, where multiple units of trHb are integrated in tandem and/or fused with another redox active or signalling domain, presenting an interesting example of gene duplication and fusion in lower eukaryotes. In contrast, trHb2_O and trHb3_P trHbs were found only in bacteria in two or multidomain organization, where amino or carboxy terminus of trHb unit is integrated with different redox-active or oxidoreductase domains. The identification of these new multiunit and chimeric trHbs and their specific phyletic distribution presents an interesting and challenging finding to explore and understand complex functionalities of these novel multidomain trHbs. © 2017 IUBMB Life, 69(7):479-488, 2017.
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Affiliation(s)
- Mangesh Dattu Hade
- Department of Biotechnology, Punjab University, Chandigarh, 160014, India.,CSIR-Institute of Microbial Technology, Sector-39A, Chandigarh, 160036, India
| | - Jagdeep Kaur
- Department of Biotechnology, Punjab University, Chandigarh, 160014, India
| | | | - Kanak L Dikshit
- Department of Biotechnology, Punjab University, Chandigarh, 160014, India
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23
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Tanner R, O’Shea MK, White AD, Müller J, Harrington-Kandt R, Matsumiya M, Dennis MJ, Parizotto EA, Harris S, Stylianou E, Naranbhai V, Bettencourt P, Drakesmith H, Sharpe S, Fletcher HA, McShane H. The influence of haemoglobin and iron on in vitro mycobacterial growth inhibition assays. Sci Rep 2017; 7:43478. [PMID: 28256545 PMCID: PMC5335253 DOI: 10.1038/srep43478] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 01/24/2017] [Indexed: 01/04/2023] Open
Abstract
The current vaccine against tuberculosis, live attenuated Mycobacterium bovis BCG, has variable efficacy, but development of an effective alternative is severely hampered by the lack of an immune correlate of protection. There has been a recent resurgence of interest in functional in vitro mycobacterial growth inhibition assays (MGIAs), which provide a measure of a range of different immune mechanisms and their interactions. We identified a positive correlation between mean corpuscular haemoglobin and in vitro growth of BCG in whole blood from healthy UK human volunteers. Mycobacterial growth in peripheral blood mononuclear cells (PBMC) from both humans and macaques was increased following the experimental addition of haemoglobin (Hb) or ferric iron, and reduced following addition of the iron chelator deferoxamine (DFO). Expression of Hb genes correlated positively with mycobacterial growth in whole blood from UK/Asian adults and, to a lesser extent, in PBMC from South African infants. Taken together our data indicate an association between Hb/iron levels and BCG growth in vitro, which may in part explain differences in findings between whole blood and PBMC MGIAs and should be considered when using such assays.
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Affiliation(s)
- Rachel Tanner
- The Jenner Institute, University of Oxford, Oxford, UK
| | | | | | - Julius Müller
- The Jenner Institute, University of Oxford, Oxford, UK
| | | | | | | | | | | | | | | | | | - Hal Drakesmith
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Sally Sharpe
- Public Health England, Porton Down, Salisbury, UK
| | | | - Helen McShane
- The Jenner Institute, University of Oxford, Oxford, UK
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24
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Structural Plasticity in Globins: Role of Protein Dynamics in Defining Ligand Migration Pathways. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 105:59-80. [PMID: 27567484 DOI: 10.1016/bs.apcsb.2016.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Globins are a family of proteins characterized by the presence of the heme prosthetic group and involved in variety of biological functions in the cell. Due to their biological relevance and widespread distribution in all kingdoms of life, intense research efforts have been devoted to disclosing the relationships between structural features, protein dynamics, and function. Particular attention has been paid to the impact of differences in amino acid sequence on the topological features of docking sites and cavities and to the influence of conformational flexibility in facilitating the migration of small ligands through these cavities. Often, tunnels are carved in the interior of globins, and ligand exchange is regulated by gating residues. Understanding the subtle intricacies that relate the differences in sequence with the structural and dynamical features of globins with the ultimate aim of rationalizing the thermodynamics and kinetics of ligand binding continues to be a major challenge in the field. Due to the evolution of computational techniques, significant advances into our understanding of these questions have been made. In this review we focus our attention on the analysis of the ligand migration pathways as well as the function of the structural cavities and tunnels in a series of representative globins, emphasizing the synergy between experimental and theoretical approaches to gain a comprehensive knowledge into the molecular mechanisms of this diverse family of proteins.
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Sethi D, Mahajan S, Singh C, Lama A, Hade MD, Gupta P, Dikshit KL. Lipoprotein LprI of Mycobacterium tuberculosis Acts as a Lysozyme Inhibitor. J Biol Chem 2015; 291:2938-53. [PMID: 26589796 DOI: 10.1074/jbc.m115.662593] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis executes numerous defense strategies for the successful establishment of infection under a diverse array of challenges inside the host. One such strategy that has been delineated in this study is the abrogation of lytic activity of lysozyme by a novel glycosylated and surface-localized lipoprotein, LprI, which is exclusively present in M. tuberculosis complex. The lprI gene co-transcribes with the glbN gene (encoding hemoglobin (HbN)) and both are synchronously up-regulated in M. tuberculosis during macrophage infection. Recombinant LprI, expressed in Escherichia coli, exhibited strong binding (Kd ≤ 2 nm) with lysozyme and abrogated its lytic activity completely, thereby conferring protection to fluorescein-labeled Micrococcus lysodeikticus from lysozyme-mediated hydrolysis. Expression of the lprI gene in Mycobacterium smegmatis (8-10-fold) protected its growth from lysozyme inhibition in vitro and enhanced its phagocytosis and survival during intracellular infection of peritoneal and monocyte-derived macrophages, known to secrete lysozyme, and in the presence of exogenously added lysozyme in secondary cell lines where lysozyme levels are low. In contrast, the presence of HbN enhanced phagocytosis and intracellular survival of M. smegmatis only in the absence of lysozyme but not under lysozyme stress. Interestingly, co-expression of the glbN-lprI gene pair elevated the invasion and survival of M. smegmatis 2-3-fold in secondary cell lines in the presence of lysozyme in comparison with isogenic cells expressing these genes individually. Thus, specific advantage against macrophage-generated lysozyme, conferred by the combination of LprI-HbN during invasion of M. tuberculosis, may have vital implications on the pathogenesis of tuberculosis.
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Affiliation(s)
- Deepti Sethi
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Sahil Mahajan
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Chaahat Singh
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Amrita Lama
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Mangesh Dattu Hade
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Pawan Gupta
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Kanak L Dikshit
- From the Council of Scientific and Industrial Research-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
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Pesce A, Bustamante JP, Bidon-Chanal A, Boechi L, Estrin DA, Luque FJ, Sebilo A, Guertin M, Bolognesi M, Ascenzi P, Nardini M. The N-terminal pre-A region of Mycobacterium tuberculosis 2/2HbN promotes NO-dioxygenase activity. FEBS J 2015; 283:305-22. [PMID: 26499089 DOI: 10.1111/febs.13571] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 08/09/2015] [Accepted: 08/16/2015] [Indexed: 01/24/2023]
Abstract
UNLABELLED A unique defense mechanisms by which Mycobacterium tuberculosis protects itself from nitrosative stress is based on the O2 -dependent NO-dioxygenase (NOD) activity of truncated hemoglobin 2/2HbN (Mt2/2HbN). The NOD activity largely depends on the efficiency of ligand migration to the heme cavity through a two-tunnel (long and short) system; recently, it was also correlated with the presence at the Mt2/2HbN N-terminus of a short pre-A region, not conserved in most 2/2HbNs, whose deletion results in a drastic reduction of NO scavenging. In the present study, we report the crystal structure of Mt2/2HbN-ΔpreA, lacking the pre-A region, at a resolution of 1.53 Å. We show that removal of the pre-A region results in long range effects on the protein C-terminus, promoting the assembly of a stable dimer, both in the crystals and in solution. In the Mt2/2HbN-ΔpreA dimer, access of heme ligands to the short tunnel is hindered. Molecular dynamics simulations show that the long tunnel branch is the only accessible pathway for O2 -ligand migration to/from the heme, and that the gating residue Phe(62)E15 partly restricts the diameter of the tunnel. Accordingly, kinetic measurements indicate that the kon value for peroxynitrite isomerization by Mt2/2HbN-ΔpreA-Fe(III) is four-fold lower relative to the full-length protein, and that NO scavenging by Mt2/2HbN-ΔpreA-Fe(II)-O2 is reduced by 35-fold. Therefore, we speculate that Mt2/2HbN evolved to host the pre-A region as a mechanism for preventing dimerization, thus reinforcing the survival of the microorganism against the reactive nitrosative stress in macrophages. DATABASE Coordinates and structure factors have been deposited in the Protein Data Bank under accession number 5AB8.
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Affiliation(s)
| | - Juan P Bustamante
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Axel Bidon-Chanal
- Departament de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, University of Barcelona, Santa Coloma de Gramenet, Spain
| | - Leonardo Boechi
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Darío A Estrin
- Departamento de Química Inorgánica, Analítica y Química Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, University of Buenos Aires, Argentina
| | - Francisco Javier Luque
- Departament de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, University of Barcelona, Santa Coloma de Gramenet, Spain
| | - Anne Sebilo
- Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Quebec, Canada
| | - Michel Guertin
- Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Quebec, Canada
| | - Martino Bolognesi
- Department of Biosciences, University of Milan, Italy.,CNR-IBF and CIMAINA, University of Milan, Italy
| | - Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, Roma Tre University, Rome, Italy.,National Institute of Biostructures and Biosystems, Rome, Italy
| | - Marco Nardini
- Department of Biosciences, University of Milan, Italy
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Rafferty SP, Dayer G. Heme proteins of Giardia intestinalis. Exp Parasitol 2015; 159:13-23. [PMID: 26297679 DOI: 10.1016/j.exppara.2015.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 08/09/2015] [Accepted: 08/10/2015] [Indexed: 10/23/2022]
Abstract
Among the few organisms that cannot make the iron cofactor heme, some nonetheless possess heme proteins. This includes the protozoan parasite Giardia intestinalis, which encodes five known heme proteins: a flavohemoglobin and four members of the cytochrome b5 family. Giardia flavohemoglobin closely resembles those of the Enterobacteriaceae in structure and function, acting as a nitric oxide dioxygenase that is induced when trophozoites are exposed to reactive nitrogen species. The Giardia cytochromes b5 are soluble proteins having relatively low reduction potentials and lack several features that are expected to promote rapid electron transfer with redox partners. Only one potential electron donor, and no electron acceptors, have yet been identified in the Giardia genome, and the roles of these cytochromes are presently unknown. The answer may lie in the sequences that flank the heme-binding core of these proteins which could serve to localize them within the cell through reversible post-translational modifications and to promote specific protein-protein interactions.
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Affiliation(s)
- Steven Patrick Rafferty
- Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada, K9J 7B8; Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada, K9J 7B8.
| | - Guillem Dayer
- Environmental and Life Sciences Graduate Program, Trent University, 1600 West Bank Drive, Peterborough, Ontario, Canada, K9J 7B8
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Merhej J, Delaveau T, Guitard J, Palancade B, Hennequin C, Garcia M, Lelandais G, Devaux F. Yap7 is a transcriptional repressor of nitric oxide oxidase in yeasts, which arose from neofunctionalization after whole genome duplication. Mol Microbiol 2015; 96:951-72. [DOI: 10.1111/mmi.12983] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Jawad Merhej
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
| | - Thierry Delaveau
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
| | - Juliette Guitard
- Sorbonne Universités, UPMC Univ Paris 06, CR7; Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris); 91 Bd de l'hôpital F-75013 Paris France
- Inserm; U1135; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
- Assistance Publique-Hôpitaux de Paris, Hôpital St Antoine; Service de Parasitologie-Mycologie; F-75012 Paris France
- CNRS; ERL 8255; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
| | - Benoit Palancade
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot; Sorbonne Paris Cité; F-75205 Paris France
| | - Christophe Hennequin
- Sorbonne Universités, UPMC Univ Paris 06, CR7; Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris); 91 Bd de l'hôpital F-75013 Paris France
- Inserm; U1135; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
- Assistance Publique-Hôpitaux de Paris, Hôpital St Antoine; Service de Parasitologie-Mycologie; F-75012 Paris France
- CNRS; ERL 8255; CIMI-Paris; 91 Bd de l'hôpital F-75013 Paris France
| | - Mathilde Garcia
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
| | - Gaëlle Lelandais
- Institut Jacques Monod, CNRS, UMR 7592, Univ Paris Diderot; Sorbonne Paris Cité; F-75205 Paris France
| | - Frédéric Devaux
- Sorbonne Universités, UPMC Univ. Paris 06, Institut de Biologie Paris Seine UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
- CNRS, UMR 7238; Laboratoire de biologie computationnelle et quantitative; F-75006 Paris France
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Peroxidase activity and involvement in the oxidative stress response of roseobacter denitrificans truncated hemoglobin. PLoS One 2015; 10:e0117768. [PMID: 25658318 PMCID: PMC4319818 DOI: 10.1371/journal.pone.0117768] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 01/01/2015] [Indexed: 11/19/2022] Open
Abstract
Roseobacter denitrificans is a member of the widespread marine Roseobacter genus. We report the first characterization of a truncated hemoglobin from R. denitrificans (Rd. trHb) that was purified in the heme-bound form from heterologous expression of the protein in Escherichia coli. Rd. trHb exhibits predominantly alpha-helical secondary structure and absorbs light at 412, 538 and 572 nm. The phylogenetic classification suggests that Rd. trHb falls into group II trHbs, whereas sequence alignments indicate that it shares certain important heme pocket residues with group I trHbs in addition to those of group II trHbs. The resonance Raman spectra indicate that the isolated Rd. trHb contains a ferric heme that is mostly 6-coordinate low-spin and that the heme of the ferrous form displays a mixture of 5- and 6-coordinate states. Two Fe-His stretching modes were detected, notably one at 248 cm-1, which has been reported in peroxidases and some flavohemoglobins that contain an Fe-His-Asp (or Glu) catalytic triad, but was never reported before in a trHb. We show that Rd. trHb exhibits a significant peroxidase activity with a (kcat/Km) value three orders of magnitude higher than that of bovine Hb and only one order lower than that of horseradish peroxidase. This enzymatic activity is pH-dependent with a pKa value ~6.8. Homology modeling suggests that residues known to be important for interactions with heme-bound ligands in group II trHbs from Mycobacterium tuberculosis and Bacillus subtilis are pointing toward to heme in Rd. trHb. Genomic organization and gene expression profiles imply possible functions for detoxification of reactive oxygen and nitrogen species in vivo. Altogether, Rd. trHb exhibits some distinctive features and appears equipped to help the bacterium to cope with reactive oxygen/nitrogen species and/or to operate redox biochemistry.
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Boron I, Bustamante JP, Davidge KS, Singh S, Bowman LA, Tinajero-Trejo M, Carballal S, Radi R, Poole RK, Dikshit K, Estrin DA, Marti MA, Boechi L. Ligand uptake in Mycobacterium tuberculosis truncated hemoglobins is controlled by both internal tunnels and active site water molecules. F1000Res 2015; 4:22. [PMID: 26478812 PMCID: PMC4591903 DOI: 10.12688/f1000research.5921.2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/20/2015] [Indexed: 11/23/2022] Open
Abstract
Mycobacterium tuberculosis, the causative agent of human tuberculosis, has two proteins belonging to the truncated hemoglobin (trHb) family. Mt-trHbN presents well-defined internal hydrophobic tunnels that allow O
2 and
•NO to migrate easily from the solvent to the active site, whereas Mt-trHbO possesses tunnels interrupted by a few bulky residues, particularly a tryptophan at position G8. Differential ligand migration rates allow Mt-trHbN to detoxify
•NO, a crucial step for pathogen survival once under attack by the immune system, much more efficiently than Mt-trHbO. In order to investigate the differences between these proteins, we performed experimental kinetic measurements,
•NO decomposition, as well as molecular dynamics simulations of the wild type
Mt-trHbN and two mutants, VG8F and VG8W. These mutations affect both the tunnels accessibility as well as the affinity of distal site water molecules, thus modifying the ligand access to the iron. We found that a single mutation allows Mt-trHbN to acquire ligand migration rates comparable to those observed for Mt-trHbO, confirming that ligand migration is regulated by the internal tunnel architecture as well as by water molecules stabilized in the active site.
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Affiliation(s)
- Ignacio Boron
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
| | - Juan Pablo Bustamante
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
| | - Kelly S Davidge
- Centre for Biomolecular Sciences, The University of Nottingham, Nottingham, NG7 2RD, UK
| | - Sandip Singh
- Institute of Microbial Technology, CSIR, Chandigarh, 160036, India
| | - Lesley Ah Bowman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Mariana Tinajero-Trejo
- Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, S10 2TN, UK
| | - Sebastián Carballal
- Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, 11100, Uruguay
| | - Rafael Radi
- Departamento de Bioquímica and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Montevideo, 11100, Uruguay
| | - Robert K Poole
- Molecular Biology and Biotechnology, The University of Sheffield, Sheffield, S10 2TN, UK
| | - Kanak Dikshit
- Institute of Microbial Technology, CSIR, Chandigarh, 160036, India
| | - Dario A Estrin
- Departamento de Química Inorgánica, Analítica y Química Física, INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
| | - Marcelo A Marti
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
| | - Leonardo Boechi
- Instituto de Cálculo, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, C1428EGA, Argentina
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Recent applications of Vitreoscilla hemoglobin technology in bioproduct synthesis and bioremediation. Appl Microbiol Biotechnol 2015; 99:1627-36. [PMID: 25575886 DOI: 10.1007/s00253-014-6350-y] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/19/2014] [Accepted: 12/21/2014] [Indexed: 10/24/2022]
Abstract
Since its first use in 1990 to enhance production of α-amylase in E. coli, engineering of heterologous hosts to express the hemoglobin from the bacterium Vitreoscilla (VHb) has become a widely used strategy to enhance production of a variety of bioproducts, stimulate bioremediation, and increase growth and survival of engineered organisms. The hosts have included a variety of bacteria, yeast, fungi, higher plants, and even animals. The beneficial effects of VHb expression are presumably the result of one or more of its activities. The available evidence indicates that these include oxygen binding and delivery to the respiratory chain and oxygenases, protection against reactive oxygen species, and control of gene expression. In the past 4 to 5 years, the use of this "VHb technology" has continued in a variety of biotechnological applications in a wide range of organisms. These include enhancement of production of an ever wider array of bioproducts, new applications in bioremediation, a possible role in enhancing aerobic waste water treatment, and the potential to enhance growth and survival of both plants and animals of economic importance.
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Ascenzi P, di Masi A, Tundo GR, Pesce A, Visca P, Coletta M. Nitrosylation mechanisms of Mycobacterium tuberculosis and Campylobacter jejuni truncated hemoglobins N, O, and P. PLoS One 2014; 9:e102811. [PMID: 25051055 PMCID: PMC4106858 DOI: 10.1371/journal.pone.0102811] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/23/2014] [Indexed: 01/19/2023] Open
Abstract
Truncated hemoglobins (trHbs) are widely distributed in bacteria and plants and have been found in some unicellular eukaryotes. Phylogenetic analysis based on protein sequences shows that trHbs branch into three groups, designated N (or I), O (or II), and P (or III). Most trHbs are involved in the O2/NO chemistry and/or oxidation/reduction function, permitting the survival of the microorganism in the host. Here, a detailed comparative analysis of kinetics and/or thermodynamics of (i) ferrous Mycobacterium tubertulosis trHbs N and O (Mt-trHbN and Mt-trHbO, respectively), and Campylobacter jejuni trHb (Cj-trHbP) nitrosylation, (ii) nitrite-mediated nitrosylation of ferrous Mt-trHbN, Mt-trHbO, and Cj-trHbP, and (iii) NO-based reductive nitrosylation of ferric Mt-trHbN, Mt-trHbO, and Cj-trHbP is reported. Ferrous and ferric Mt-trHbN and Cj-trHbP display a very high reactivity towards NO; however, the conversion of nitrite to NO is facilitated primarily by ferrous Mt-trHbN. Values of kinetic and/or thermodynamic parameters reflect specific trHb structural features, such as the ligand diffusion pathways to/from the heme, the heme distal pocket structure and polarity, and the ligand stabilization mechanisms. In particular, the high reactivity of Mt-trHbN and Cj-trHbP reflects the great ligand accessibility to the heme center by two protein matrix tunnels and the E7-path, respectively, and the penta-coordination of the heme-Fe atom. In contrast, the heme-Fe atom of Mt-trHbO the ligand accessibility to the heme center of Mt-trHbO needs large conformational readjustments, thus limiting the heme-based reactivity. These results agree with different roles of Mt-trHbN, Mt-trHbO, and Cj-trHbP in vivo.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
- * E-mail:
| | - Alessandra di Masi
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
- Department of Sciences, University Roma Tre, Roma, Italy
| | - Grazia R. Tundo
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
| | | | - Paolo Visca
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy
| | - Massimo Coletta
- Department of Clinical Sciences and Translational Medicine, University of Roma “Tor Vergata”, Roma, Italy
- Interuniversity Consortium for the Research on the Chemistry of Metals in Biological Systems, Bari, Italy
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Comparison of gene expression of immune mediators in lung and pulmonary lymph node granulomas from cattle experimentally infected with Mycobacterium bovis. Vet Immunol Immunopathol 2014; 160:81-9. [DOI: 10.1016/j.vetimm.2014.03.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 03/18/2014] [Accepted: 03/29/2014] [Indexed: 12/26/2022]
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Kim DY, Hong MJ, Seo YW. Role of wheat trHb in nitric oxide scavenging. Mol Biol Rep 2014; 41:5931-41. [DOI: 10.1007/s11033-014-3468-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2013] [Accepted: 06/14/2014] [Indexed: 12/21/2022]
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Singh S, Thakur N, Oliveira A, Petruk AA, Hade MD, Sethi D, Bidon-Chanal A, Martí MA, Datta H, Parkesh R, Estrin DA, Luque FJ, Dikshit KL. Mechanistic insight into the enzymatic reduction of truncated hemoglobin N of Mycobacterium tuberculosis: role of the CD loop and pre-A motif in electron cycling. J Biol Chem 2014; 289:21573-83. [PMID: 24928505 DOI: 10.1074/jbc.m114.578187] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Many pathogenic microorganisms have evolved hemoglobin-mediated nitric oxide (NO) detoxification mechanisms, where a globin domain in conjunction with a partner reductase catalyzes the conversion of toxic NO to innocuous nitrate. The truncated hemoglobin HbN of Mycobacterium tuberculosis displays a potent NO dioxygenase activity despite lacking a reductase domain. The mechanism by which HbN recycles itself during NO dioxygenation and the reductase that participates in this process are currently unknown. This study demonstrates that the NADH-ferredoxin/flavodoxin system is a fairly efficient partner for electron transfer to HbN with an observed reduction rate of 6.2 μM/min(-1), which is nearly 3- and 5-fold faster than reported for Vitreoscilla hemoglobin and myoglobin, respectively. Structural docking of the HbN with Escherichia coli NADH-flavodoxin reductase (FdR) together with site-directed mutagenesis revealed that the CD loop of the HbN forms contacts with the reductase, and that Gly(48) may have a vital role. The donor to acceptor electron coupling parameters calculated using the semiempirical pathway method amounts to an average of about 6.4 10(-5) eV, which is lower than the value obtained for E. coli flavoHb (8.0 10(-4) eV), but still supports the feasibility of an efficient electron transfer. The deletion of Pre-A abrogated the heme iron reduction by FdR in the HbN, thus signifying its involvement during intermolecular interactions of the HbN and FdR. The present study, thus, unravels a novel role of the CD loop and Pre-A motif in assisting the interactions of the HbN with the reductase and the electron cycling, which may be vital for its NO-scavenging function.
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Affiliation(s)
- Sandeep Singh
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Naveen Thakur
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Ana Oliveira
- the Department de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, Universitat de Barcelona, Campus de l'Alimentació Torribera, Santa Coloma de Gramenet, Spain, and
| | - Ariel A Petruk
- the Departamento de Química Inorgánica, Analítica, y Química Física/INQUIMAE CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Mangesh Dattu Hade
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Deepti Sethi
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Axel Bidon-Chanal
- the Department de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, Universitat de Barcelona, Campus de l'Alimentació Torribera, Santa Coloma de Gramenet, Spain, and
| | - Marcelo A Martí
- the Departamento de Química Inorgánica, Analítica, y Química Física/INQUIMAE CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - Himani Datta
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Raman Parkesh
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
| | - Dario A Estrin
- the Departamento de Química Inorgánica, Analítica, y Química Física/INQUIMAE CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, C1428EHA Buenos Aires, Argentina
| | - F Javier Luque
- the Department de Fisicoquímica and Institut de Biomedicina (IBUB), Facultat de Farmàcia, Universitat de Barcelona, Campus de l'Alimentació Torribera, Santa Coloma de Gramenet, Spain, and
| | - Kanak L Dikshit
- From the CSIR-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India,
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Thakur N, Gupta S, Hade MD, Dikshit KL. Type I flavohemoglobin of mycobacterium smegmatis is a functional nitric oxide dioxygenase. IUBMB Life 2014; 66:396-404. [PMID: 24861678 DOI: 10.1002/iub.1275] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 05/06/2014] [Indexed: 12/12/2022]
Abstract
Two flavohemoglobins, type I and type II, displaying distinct structural features and cofactor binding sites coexist in Mycobacterium smegmatis; however, none of these flavohemeproteins are characterized so far. We have cloned and expressed type I flavohemoglobin (FHb1) of Mycobacterium smegmatis, encoded by MSMEG_1336, and characterized its spectral and functional properties. FHb1 exists as a monomer and displays spectral and functional characteristics similar to HMP of E. coli. Specific NO dioxygenase (NOD) activity of FHb1 was estimated to be 63.5 nmol heme(-1) sec(-1) , which was nearly eightfold higher than the HbN of M. tuberculosis and matched closely to the HMP of E. coli on the basis of cellular heme content. FHb1 preferred NADH for the NO dioxygenation and exhibited rapid reduction of flavin adenine dinucleotide and heme iron using NADH as electron donor. Level of FHb1 transcript increased significantly in M. smegmatis in the presence of acidified nitrite, and a nitric oxide-responsive transcriptional regulator of Rrf2 family exists together with the FHb1 under the same operon. These results suggested that FHb1 of M. smegmatis is a functional NOD and may be involved in the stress management of its host toward nitric oxide and nitrosative stress.
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Affiliation(s)
- Naveen Thakur
- CSIR-Institute of Microbial Technology, Sector 39 A, Chandigarh, India
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Giordano D, Coppola D, Russo R, Tinajero-Trejo M, di Prisco G, Lauro F, Ascenzi P, Verde C. The globins of cold-adapted Pseudoalteromonas haloplanktis TAC125: from the structure to the physiological functions. Adv Microb Physiol 2014; 63:329-89. [PMID: 24054800 DOI: 10.1016/b978-0-12-407693-8.00008-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Evolution allowed Antarctic microorganisms to grow successfully under extreme conditions (low temperature and high O2 content), through a variety of structural and physiological adjustments in their genomes and development of programmed responses to strong oxidative and nitrosative stress. The availability of genomic sequences from an increasing number of cold-adapted species is providing insights to understand the molecular mechanisms underlying crucial physiological processes in polar organisms. The genome of Pseudoalteromonas haloplanktis TAC125 contains multiple genes encoding three distinct truncated globins exhibiting the 2/2 α-helical fold. One of these globins has been extensively characterised by spectroscopic analysis, kinetic measurements and computer simulation. The results indicate unique adaptive structural properties that enhance the overall flexibility of the protein, so that the structure appears to be resistant to pressure-induced stress. Recent results on a genomic mutant strain highlight the involvement of the cold-adapted globin in the protection against the stress induced by high O2 concentration. Moreover, the protein was shown to catalyse peroxynitrite isomerisation in vitro. In this review, we first summarise how cold temperatures affect the physiology of microorganisms and focus on the molecular mechanisms of cold adaptation revealed by recent biochemical and genetic studies. Next, since only in a very few cases the physiological role of truncated globins has been demonstrated, we also discuss the structural and functional features of the cold-adapted globin in an attempt to put into perspective what has been learnt about these proteins and their potential role in the biology of cold-adapted microorganisms.
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Abstract
Small size globins that have been defined as 'truncated haemoglobins' or as '2/2 haemoglobins' have increasingly been discovered in microorganisms since the early 1990s. Analysis of amino acid sequences allowed to distinguish three groups that collect proteins with specific and common structural properties. All three groups display 3D structures that are based on four main α-helices, which are a subset of the conventional eight-helices globin fold. Specific features, such as the presence of protein matrix tunnels that are held to promote diffusion of functional ligands to/from the haem, distinguish members of the three groups. Haem distal sites vary for their accessibility, local structures, polarity, and ligand stabilization mechanisms, suggesting functional roles that are related to O2/NO chemistry. In a few cases, such activities have been proven in vitro and in vivo through deletion mutants. The issue of 2/2 haemoglobin varied biological functions throughout the three groups remains however fully open.
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Abstract
The genus Mycobacterium is comprised of Gram-positive bacteria occupying a wide range of natural habitats and includes species that range from severe intracellular pathogens to economically useful and harmless microbes. The recent upsurge in the availability of microbial genome data has shown that genes encoding haemoglobin-like proteins are ubiquitous among Mycobacteria and that multiple haemoglobins (Hbs) of different classes may be present in pathogenic and non-pathogenic species. The occurrence of truncated haemoglobins (trHbs) and flavohaemoglobins (flavoHbs) showing distinct haem active site structures and ligand-binding properties suggests that these Hbs may be playing diverse functions in the cellular metabolism of Mycobacteria. TrHbs and flavoHbs from some of the severe human pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae have been studied recently and their roles in effective detoxification of reactive nitrogen and oxygen species, electron cycling, modulation of redox state of the cell and facilitation of aerobic respiration have been proposed. This multiplicity in the function of Hbs may aid these pathogens to cope with various environmental stresses and survive during their intracellular regime. This chapter provides recent updates on genomic, structural and functional aspects of Mycobacterial Hbs to address their role in Mycobacteria.
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Stern AM, Zhu J. An introduction to nitric oxide sensing and response in bacteria. ADVANCES IN APPLIED MICROBIOLOGY 2014; 87:187-220. [PMID: 24581392 DOI: 10.1016/b978-0-12-800261-2.00005-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Nitric oxide (NO) is a radical gas that has been intensively studied for its role as a bacteriostatic agent. NO reacts in complex ways with biological molecules, especially metal centers and other radicals, to generate other bioactive compounds that inhibit enzymes, oxidize macromolecules, and arrest bacterial growth. Bacteria encounter not only NO derived from the host during infection but also NO derived from other bacteria and inorganic sources. The transcriptional responses used by bacteria to respond to NO are diverse but usually involve an iron-containing transcription factor that binds NO and alters its affinity for either DNA or factors involved in transcription, leading to the production of enzymatic tolerance systems. Some of these systems, such as flavohemoglobin and flavorubredoxin, directly remove NO. Some do not but are still important for NO tolerance through other mechanisms. The targets of NO that are protected by these systems include many metabolic pathways such as the tricarboxylic acid cycle and branched chain amino acid synthesis. This chapter discusses these topics and others and serves as a general introduction to microbial NO biology.
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Arya S, Sethi D, Singh S, Hade MD, Singh V, Raju P, Chodisetti SB, Verma D, Varshney GC, Agrewala JN, Dikshit KL. Truncated hemoglobin, HbN, is post-translationally modified in Mycobacterium tuberculosis and modulates host-pathogen interactions during intracellular infection. J Biol Chem 2013; 288:29987-99. [PMID: 23983123 DOI: 10.1074/jbc.m113.507301] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Mycobacterium tuberculosis (Mtb) is a phenomenally successful human pathogen having evolved mechanisms that allow it to survive within the hazardous environment of macrophages and establish long term, persistent infection in the host against the control of cell-mediated immunity. One such mechanism is mediated by the truncated hemoglobin, HbN, of Mtb that displays a potent O2-dependent nitric oxide dioxygenase activity and protects its host from the toxicity of macrophage-generated nitric oxide (NO). Here we demonstrate for the first time that HbN is post-translationally modified by glycosylation in Mtb and remains localized on the cell membrane and the cell wall. The glycan linkage in the HbN was identified as mannose. The elevated expression of HbN in Mtb and M. smegmatis facilitated their entry within the macrophages as compared with isogenic control cells, and mutation in the glycan linkage of HbN disrupted this effect. Additionally, HbN-expressing cells exhibited higher survival within the THP-1 and mouse peritoneal macrophages, simultaneously increasing the intracellular level of proinflammatory cytokines IL-6 and TNF-α and suppressing the expression of co-stimulatory surface markers CD80 and CD86. These results, thus, suggest the involvement of HbN in modulating the host-pathogen interactions and immune system of the host apart from protecting the bacilli from nitrosative stress inside the activated macrophages, consequently driving cells toward increased infectivity and intracellular survival.
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Affiliation(s)
- Swati Arya
- From the Council of Scientific and Industrial Research (CSIR)-Institute of Microbial Technology, Sector 39A, Chandigarh 160036, India
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Ascenzi P, Coletta A, Cao Y, Trezza V, Leboffe L, Fanali G, Fasano M, Pesce A, Ciaccio C, Marini S, Coletta M. Isoniazid inhibits the heme-based reactivity of Mycobacterium tuberculosis truncated hemoglobin N. PLoS One 2013; 8:e69762. [PMID: 23936350 PMCID: PMC3731299 DOI: 10.1371/journal.pone.0069762] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 06/12/2013] [Indexed: 11/19/2022] Open
Abstract
Isoniazid represents a first-line anti-tuberculosis medication in prevention and treatment. This prodrug is activated by a mycobacterial catalase-peroxidase enzyme called KatG in Mycobacterium tuberculosis), thereby inhibiting the synthesis of mycolic acid, required for the mycobacterial cell wall. Moreover, isoniazid activation by KatG produces some radical species (e.g., nitrogen monoxide), that display anti-mycobacterial activity. Remarkably, the ability of mycobacteria to persist in vivo in the presence of reactive nitrogen and oxygen species implies the presence in these bacteria of (pseudo-)enzymatic detoxification systems, including truncated hemoglobins (trHbs). Here, we report that isoniazid binds reversibly to ferric and ferrous M. tuberculosis trHb type N (or group I; Mt-trHbN(III) and Mt-trHbN(II), respectively) with a simple bimolecular process, which perturbs the heme-based spectroscopic properties. Values of thermodynamic and kinetic parameters for isoniazid binding to Mt-trHbN(III) and Mt-trHbN(II) are K = (1.1±0.1)×10−4 M, kon = (5.3±0.6)×103 M−1 s−1 and koff = (4.6±0.5)×10−1 s−1; and D = (1.2±0.2)×10−3 M, don = (1.3±0.4)×103 M−1 s−1, and doff = 1.5±0.4 s−1, respectively, at pH 7.0 and 20.0°C. Accordingly, isoniazid inhibits competitively azide binding to Mt-trHbN(III) and Mt-trHbN(III)-catalyzed peroxynitrite isomerization. Moreover, isoniazid inhibits Mt-trHbN(II) oxygenation and carbonylation. Although the structure of the Mt-trHbN-isoniazid complex is not available, here we show by docking simulation that isoniazid binding to the heme-Fe atom indeed may take place. These data suggest a direct role of isoniazid to impair fundamental functions of mycobacteria, e.g. scavenging of reactive nitrogen and oxygen species, and metabolism.
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Affiliation(s)
- Paolo Ascenzi
- Interdepartmental Laboratory of Electron Microscopy, University Roma Tre, Roma, Italy.
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Nitric oxide reactivities of the two globins of the foodborne pathogen Campylobacter jejuni: roles in protection from nitrosative stress and analysis of potential reductants. Nitric Oxide 2013; 34:65-75. [PMID: 23764490 DOI: 10.1016/j.niox.2013.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 05/30/2013] [Accepted: 06/03/2013] [Indexed: 12/29/2022]
Abstract
BACKGROUND During infection and pathogenesis, Campylobacter, the leading cause of gastroenteritis, encounters NO and reactive nitrogen species (RNS) derived from the host. To combat these species, Campylobacter jejuni expresses two haemoglobins: the single domain haemoglobin (Cgb) detoxifies NO but the role of the truncated globin (Ctb) is unclear. Confirmation of Cgb activity and more extensive exploration of Ctb function(s) in vivo are restricted due to difficulties in expressing proteins in Campylobacter and our lack of understanding of how the globin haems are re-reduced after ligand reactions. METHODS The cgb and ctb genes were cloned under the control of arabinose-inducible promoters and the globins expressed in an Escherichia coli mutant lacking the main NO detoxification mechanisms (Hmp and the Nor system comprising the transcription regulator NorR, the flavorubredoxin and its reductase (NorVW)); cellular responses under oxidative and nitrosative stress conditions were assessed. Spectroscopic changes of the Cgb and Ctb haems in soluble fractions after oxidation by NO were evaluated. Construction of E. coli nor mutants and a ubiquinone-defective strain allowed the exploration of the flavorubredoxin reductase and the aerobic respiratory chain as candidates for Cgb electron donors in E. coli mutants. RESULTS Cgb, but not Ctb, complements the NO- and RNS-sensitive phenotype of an E. coli hmp mutant in aerobic conditions; however, Cgb fails to protect an hmp norR mutant in the absence of oxygen. Reduction of Cgb and Ctb in E. coli and C. jejuni soluble extracts and turnover after NO oxidation is demonstrated. Finally, we report a minor role for NorW as a Cgb reductase partner in E. coli but no role for respiratory electron flux in globin redox cycling. CONCLUSIONS The NO detoxification capacity of Cgb is confirmed by heterologous expression in E. coli. The reducibility of Cgb and Ctb in E. coli and C. jejuni extracts and the lack of dependence of reduction upon flavorubredoxin reductase and the respiratory chain in E. coli argue in favor of a non-specific reductase system. GENERAL SIGNIFICANCE We present the most persuasive evidence to date that Cgb, but not Ctb, confers tolerance to NO and RNS by reaction with NO. Since certain hypotheses for the mechanism of haem re-reduction in E. coli following the reaction with NO are not proven, the mechanisms of reduction in C. jejuni now require challenging experimental evaluation.
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Abbruzzetti S, Spyrakis F, Bidon-Chanal A, Luque FJ, Viappiani C. Ligand migration through hemeprotein cavities: insights from laser flash photolysis and molecular dynamics simulations. Phys Chem Chem Phys 2013; 15:10686-701. [PMID: 23733145 DOI: 10.1039/c3cp51149a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The presence of cavities and tunnels in the interior of proteins, in conjunction with the structural plasticity arising from the coupling to the thermal fluctuations of the protein scaffold, has profound consequences on the pathways followed by ligands moving through the protein matrix. In this perspective we discuss how quantitative analysis of experimental rebinding kinetics from laser flash photolysis, trapping of unstable conformational states by embedding proteins within the nanopores of silica gels, and molecular simulations can synergistically converge to gain insight into the migration mechanism of ligands. We show how the evaluation of the free energy landscape for ligand diffusion based on the outcome of computational techniques can assist the definition of sound reaction schemes, leading to a comprehensive understanding of the broad range of chemical events and time scales that encompass the transport of small ligands in hemeproteins.
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Affiliation(s)
- Stefania Abbruzzetti
- Dipartimento di Fisica e Scienze della Terra, Università degli Studi di Parma, viale delle Scienze 7A, 43124, Parma, Italy
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Coppola D, Giordano D, Tinajero-Trejo M, di Prisco G, Ascenzi P, Poole RK, Verde C. Antarctic bacterial haemoglobin and its role in the protection against nitrogen reactive species. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1923-31. [PMID: 23434851 DOI: 10.1016/j.bbapap.2013.02.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 02/11/2013] [Accepted: 02/12/2013] [Indexed: 01/25/2023]
Abstract
In a cold and oxygen-rich environment such as Antarctica, mechanisms for the defence against reactive oxygen and nitrogen species are needed and represent important components in the evolutionary adaptations. In the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125, the presence of multiple genes encoding 2/2 haemoglobins and a flavohaemoglobin strongly suggests that these proteins fulfil important physiological roles, perhaps associated to the peculiar features of the Antarctic habitat. In this work, the putative role of Ph-2/2HbO, encoded by the PSHAa0030 gene, was investigated by in vivo and in vitro experiments in order to highlight its involvement in NO detoxification mechanisms. The PSHAa0030 gene was cloned and then over-expressed in a flavohaemoglobin-deficient mutant of Escherichia coli, unable to metabolise NO, and the resulting strain was studied analysing its growth properties and oxygen uptake in the presence of NO. We here demonstrate that Ph-2/2HbO protects growth and cellular respiration of the heterologous host from the toxic effect of NO-donors. Unlike in Mycobacterium tuberculosis 2/2 HbN, the deletion of the N-terminal extension of Ph-2/2HbO does not seem to reduce the NO scavenging activity, showing that the N-terminal extension is not a requirement for efficient NO detoxification. Moreover, the ferric form of Ph-2/2HbO was shown to catalyse peroxynitrite isomerisation in vitro, confirming its potential role in the scavenging of reactive nitrogen species. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.
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Affiliation(s)
- Daniela Coppola
- Institute of Protein Biochemistry, CNR, Via Pietro Castellino 111, Naples, Italy
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Laver JR, McLean S, Bowman LAH, Harrison LJ, Read RC, Poole RK. Nitrosothiols in bacterial pathogens and pathogenesis. Antioxid Redox Signal 2013; 18:309-22. [PMID: 22768799 DOI: 10.1089/ars.2012.4767] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
SIGNIFICANCE The formation and degradation of S-nitrosothiols (SNOs) are important mechanisms of post-translational protein modification and appear to be ubiquitous in biology. These processes play well-characterized roles in eukaryotic cells, including a variety of pathologies and in relation to chronic conditions. We know little of the roles of these processes in pathogenic and other bacteria. RECENT ADVANCES It is clear, mostly from growth and transcriptional studies, that bacteria sense and respond to exogenous SNOs. These responses are phenotypically and mechanistically distinct from the responses of bacteria to nitric oxide (NO) and NO-releasing agents, as well as peroxynitrite. Small SNOs, such as S-nitrosoglutathione (GSNO), are accumulated by bacteria with the result that intracellular S-nitrosoproteins (the 'S-nitrosoproteome') are detectable. Recently, conditions for endogenous SNO formation in enterobacteria have been described. CRITICAL ISSUES The propensity of intracellular proteins to form SNOs is presumably constrained by the same rules of selectivity that have been discovered in eukaryotic systems, but is also influenced by uniquely bacterial NO detoxification systems, exemplified by the flavohemoglobin Hmp in enterobacteria and NO reductase of meningococci. Furthermore, the bacterial expression of such proteins impacts upon the formation of SNOs in mammalian hosts. FUTURE DIRECTIONS The impairment during bacterial infections of specific SNO events in the mammalian host is of considerable interest in the context of proteins involved in innate immunity and intracellular signalling. In bacteria, numerous mechanisms of S-nitrosothiol degradation have been reported (e.g., GSNO reductase); others are thought to operate, based on consideration of their mammalian counterparts. The nitrosothiols of bacteria and particularly of pathogens warrant more intensive investigation.
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Affiliation(s)
- Jay R Laver
- Department of Infection and Immunity, The University of Sheffield, Sheffield, United Kingdom.
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Abstract
Campylobacter jejuni is a zoonotic Gram-negative bacterial pathogen that is exposed to reactive nitrogen species, such as nitric oxide, from a variety of sources. To combat the toxic effects of this nitrosative stress, C. jejuni upregulates a small regulon under the control of the transcriptional activator NssR, which positively regulates the expression of a single-domain globin protein (Cgb) and a truncated globin protein (Ctb). Cgb has previously been shown to detoxify nitric oxide, but the role of Ctb remains contentious. As C. jejuni is amenable to genetic manipulation, and its globin proteins are easily expressed and purified, a combination of mutagenesis, complementation, transcriptomics, spectroscopic characterisation and structural analyses has been used to probe the regulation, function and structure of Cgb and Ctb. This ability to study Cgb and Ctb with such a multi-pronged approach is a valuable asset, especially since only a small fraction of known globin proteins have been functionally characterised.
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Miramón P, Dunker C, Windecker H, Bohovych IM, Brown AJP, Kurzai O, Hube B. Cellular responses of Candida albicans to phagocytosis and the extracellular activities of neutrophils are critical to counteract carbohydrate starvation, oxidative and nitrosative stress. PLoS One 2012; 7:e52850. [PMID: 23285201 PMCID: PMC3528649 DOI: 10.1371/journal.pone.0052850] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 11/21/2012] [Indexed: 11/19/2022] Open
Abstract
Neutrophils are key players during Candida albicans infection. However, the relative contributions of neutrophil activities to fungal clearance and the relative importance of the fungal responses that counteract these activities remain unclear. We studied the contributions of the intra- and extracellular antifungal activities of human neutrophils using diagnostic Green Fluorescent Protein (GFP)-marked C. albicans strains. We found that a carbohydrate starvation response, as indicated by up-regulation of glyoxylate cycle genes, was only induced upon phagocytosis of the fungus. Similarly, the nitrosative stress response was only observed in internalised fungal cells. In contrast, the response to oxidative stress was observed in both phagocytosed and non-phagocytosed fungal cells, indicating that oxidative stress is imposed both intra- and extracellularly. We assessed the contributions of carbohydrate starvation, oxidative and nitrosative stress as antifungal activities by analysing the resistance to neutrophil killing of C. albicans mutants lacking key glyoxylate cycle, oxidative and nitrosative stress genes. We found that the glyoxylate cycle plays a crucial role in fungal resistance against neutrophils. The inability to respond to oxidative stress (in cells lacking superoxide dismutase 5 or glutathione reductase 2) renders C. albicans susceptible to neutrophil killing, due to the accumulation of reactive oxygen species (ROS). We also show that neutrophil-derived nitric oxide is crucial for the killing of C. albicans: a yhb1Δ/Δ mutant, unable to detoxify NO•, was more susceptible to neutrophils, and this phenotype was rescued by the nitric oxide scavenger carboxy-PTIO. The stress responses of C. albicans to neutrophils are partially regulated via the stress regulator Hog1 since a hog1Δ/Δ mutant was clearly less resistant to neutrophils and unable to respond properly to neutrophil-derived attack. Our data indicate that an appropriate fungal response to all three antifungal activities, carbohydrate starvation, nitrosative stress and oxidative stress, is essential for full wild type resistance to neutrophils.
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Affiliation(s)
- Pedro Miramón
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Christine Dunker
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Hanna Windecker
- Septomics Research Centre, Friedrich Schiller University and Leibniz Institute for Natural Products Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Iryna M. Bohovych
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Alistair J. P. Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Oliver Kurzai
- Septomics Research Centre, Friedrich Schiller University and Leibniz Institute for Natural Products Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
- Center for Sepsis Control and Care, Universitätsklinikum Jena, Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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Gardner PR. Hemoglobin: a nitric-oxide dioxygenase. SCIENTIFICA 2012; 2012:683729. [PMID: 24278729 PMCID: PMC3820574 DOI: 10.6064/2012/683729] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 10/04/2012] [Indexed: 05/09/2023]
Abstract
Members of the hemoglobin superfamily efficiently catalyze nitric-oxide dioxygenation, and when paired with native electron donors, function as NO dioxygenases (NODs). Indeed, the NOD function has emerged as a more common and ancient function than the well-known role in O2 transport-storage. Novel hemoglobins possessing a NOD function continue to be discovered in diverse life forms. Unique hemoglobin structures evolved, in part, for catalysis with different electron donors. The mechanism of NOD catalysis by representative single domain hemoglobins and multidomain flavohemoglobin occurs through a multistep mechanism involving O2 migration to the heme pocket, O2 binding-reduction, NO migration, radical-radical coupling, O-atom rearrangement, nitrate release, and heme iron re-reduction. Unraveling the physiological functions of multiple NODs with varying expression in organisms and the complexity of NO as both a poison and signaling molecule remain grand challenges for the NO field. NOD knockout organisms and cells expressing recombinant NODs are helping to advance our understanding of NO actions in microbial infection, plant senescence, cancer, mitochondrial function, iron metabolism, and tissue O2 homeostasis. NOD inhibitors are being pursued for therapeutic applications as antibiotics and antitumor agents. Transgenic NOD-expressing plants, fish, algae, and microbes are being developed for agriculture, aquaculture, and industry.
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Affiliation(s)
- Paul R. Gardner
- Miami Valley Biotech, 1001 E. 2nd Street, Suite 2445, Dayton, OH 45402, USA
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Role of PheE15 gate in ligand entry and nitric oxide detoxification function of mycobacterium tuberculosis truncated hemoglobin N. PLoS One 2012; 7:e49291. [PMID: 23145144 PMCID: PMC3493545 DOI: 10.1371/journal.pone.0049291] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2012] [Accepted: 10/08/2012] [Indexed: 11/19/2022] Open
Abstract
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.
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