1
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Yoo BK, Kruglik SG, Lambry JC, Lamarre I, Raman CS, Nioche P, Negrerie M. The H-NOX protein structure adapts to different mechanisms in sensors interacting with nitric oxide. Chem Sci 2023; 14:8408-8420. [PMID: 37564404 PMCID: PMC10411614 DOI: 10.1039/d3sc01685d] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/05/2023] [Indexed: 08/12/2023] Open
Abstract
Some classes of bacteria within phyla possess protein sensors identified as homologous to the heme domain of soluble guanylate cyclase, the mammalian NO-receptor. Named H-NOX domain (Heme-Nitric Oxide or OXygen-binding), their heme binds nitric oxide (NO) and O2 for some of them. The signaling pathways where these proteins act as NO or O2 sensors appear various and are fully established for only some species. Here, we investigated the reactivity of H-NOX from bacterial species toward NO with a mechanistic point of view using time-resolved spectroscopy. The present data show that H-NOXs modulate the dynamics of NO as a function of temperature, but in different ranges, changing its affinity by changing the probability of NO rebinding after dissociation in the picosecond time scale. This fundamental mechanism provides a means to adapt the heme structural response to the environment. In one particular H-NOX sensor the heme distortion induced by NO binding is relaxed in an ultrafast manner (∼15 ps) after NO dissociation, contrarily to other H-NOX proteins, providing another sensing mechanism through the H-NOX domain. Overall, our study links molecular dynamics with functional mechanism and adaptation.
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Affiliation(s)
- Byung-Kuk Yoo
- Laboratoire d'Optique et Biosciences, INSERM U-1182, Ecole Polytechnique 91120 Palaiseau France
| | - Sergei G Kruglik
- Laboratoire Jean Perrin, Institut de Biologie Paris-Seine, Sorbonne Université, CNRS 75005 Paris France
| | - Jean-Christophe Lambry
- Laboratoire d'Optique et Biosciences, INSERM U-1182, Ecole Polytechnique 91120 Palaiseau France
| | - Isabelle Lamarre
- Laboratoire d'Optique et Biosciences, INSERM U-1182, Ecole Polytechnique 91120 Palaiseau France
| | - C S Raman
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland Baltimore Maryland 21201 USA
| | - Pierre Nioche
- Environmental Toxicity, Therapeutic Targets, Cellular Signaling and Biomarkers, UMR S1124, Centre Universitaire des Saints-Pères, Université Paris Descartes 75006 Paris France
- Structural and Molecular Analysis Platform, BioMedTech Facilities, INSERM US36-CNRS-UMS2009, Paris Université Paris France
| | - Michel Negrerie
- Laboratoire d'Optique et Biosciences, INSERM U-1182, Ecole Polytechnique 91120 Palaiseau France
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2
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Négrerie M. Iron transitions during activation of allosteric heme proteins in cell signaling. Metallomics 2020; 11:868-893. [PMID: 30957812 DOI: 10.1039/c8mt00337h] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Allosteric heme proteins can fulfill a very large number of different functions thanks to the remarkable chemical versatility of heme through the entire living kingdom. Their efficacy resides in the ability of heme to transmit both iron coordination changes and iron redox state changes to the protein structure. Besides the properties of iron, proteins may impose a particular heme geometry leading to distortion, which allows selection or modulation of the electronic properties of heme. This review focusses on the mechanisms of allosteric protein activation triggered by heme coordination changes following diatomic binding to proteins as diverse as the human NO-receptor, cytochromes, NO-transporters and sensors, and a heme-activated potassium channel. It describes at the molecular level the chemical capabilities of heme to achieve very different tasks and emphasizes how the properties of heme are determined by the protein structure. Particularly, this reviews aims at giving an overview of the exquisite adaptability of heme, from bacteria to mammals.
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Affiliation(s)
- Michel Négrerie
- Laboratoire d'Optique et Biosciences, INSERM, CNRS, Ecole Polytechnique, 91120 Palaiseau, France.
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3
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Guo Y, Marletta MA. Structural Insight into H‐NOX Gas Sensing and Cognate Signaling Protein Regulation. Chembiochem 2018; 20:7-19. [DOI: 10.1002/cbic.201800478] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Indexed: 11/06/2022]
Affiliation(s)
- Yirui Guo
- California Institute for Quantitative BiosciencesUniversity of California, Berkeley Berkeley, CA 94720 USA
| | - Michael A. Marletta
- California Institute for Quantitative BiosciencesUniversity of California, Berkeley Berkeley, CA 94720 USA
- Department of Molecular and Cell BiologyUniversity of California, Berkeley Berkeley, CA 94720 USA
- Department of ChemistryUniversity of California, Berkeley Berkeley, CA 94720 USA
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4
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Regulation of nitric oxide signaling by formation of a distal receptor-ligand complex. Nat Chem Biol 2017; 13:1216-1221. [PMID: 28967923 PMCID: PMC5698159 DOI: 10.1038/nchembio.2488] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 08/28/2017] [Indexed: 12/23/2022]
Abstract
The binding of nitric oxide (NO) to the heme cofactor of heme-nitric oxide/oxygen binding (H-NOX) proteins can lead to the dissociation of the heme-ligating histidine residue and yield a five-coordinate nitrosyl complex, which is an important step for NO-dependent signaling. In the five-coordinate nitrosyl complex, NO can reside either on the distal or proximal side of the heme, which could have a profound influence over the lifetime of the in vivo signal. To investigate this central molecular question, the Shewanella oneidensis H-NOX (So H-NOX)–NO complex was biophysically characterized under limiting and excess NO. The results show that So H-NOX preferably forms a distal NO species under both limiting and excess NO. Therefore, signal strength and complex lifetime in vivo will be dictated by the dissociation rate of NO from the distal complex and the return of the histidine ligand to the heme.
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5
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Kekilli D, Petersen CA, Pixton DA, Ghafoor DD, Abdullah GH, Dworkowski FSN, Wilson MT, Heyes DJ, Hardman SJO, Murphy LM, Strange RW, Scrutton NS, Andrew CR, Hough MA. Engineering proximal vs. distal heme-NO coordination via dinitrosyl dynamics: implications for NO sensor design. Chem Sci 2017; 8:1986-1994. [PMID: 28451315 PMCID: PMC5390784 DOI: 10.1039/c6sc04190f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 11/08/2016] [Indexed: 01/18/2023] Open
Abstract
Proximal vs. distal heme-NO coordination is a novel strategy for selective gas response in heme-based NO-sensors. In the case of Alcaligenes xylosoxidans cytochrome c' (AXCP), formation of a transient distal 6cNO complex is followed by scission of the trans Fe-His bond and conversion to a proximal 5cNO product via a putative dinitrosyl species. Here we show that replacement of the AXCP distal Leu16 residue with smaller or similar sized residues (Ala, Val or Ile) traps the distal 6cNO complex, whereas Leu or Phe residues lead to a proximal 5cNO product with a transient or non-detectable distal 6cNO precursor. Crystallographic, spectroscopic, and kinetic measurements of 6cNO AXCP complexes show that increased distal steric hindrance leads to distortion of the Fe-N-O angle and flipping of the heme 7-propionate. However, it is the kinetic parameters of the distal NO ligand that determine whether 6cNO or proximal 5cNO end products are formed. Our data support a 'balance of affinities' mechanism in which proximal 5cNO coordination depends on relatively rapid release of the distal NO from the dinitrosyl precursor. This mechanism, which is applicable to other proteins that form transient dinitrosyls, represents a novel strategy for 5cNO formation that does not rely on an inherently weak Fe-His bond. Our data suggest a general means of engineering selective gas response into biologically-derived gas sensors in synthetic biology.
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Affiliation(s)
- Demet Kekilli
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Christine A Petersen
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - David A Pixton
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Dlzar D Ghafoor
- Faculty of Science and Education Science , University of Sulaimani , Sulaymaniyah , Iraq
| | | | | | - Michael T Wilson
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
| | - Derren J Heyes
- Manchester Institute of Biotechnology , 131 Princess Street , Manchester M1 7DN , UK
| | - Samantha J O Hardman
- Manchester Institute of Biotechnology , 131 Princess Street , Manchester M1 7DN , UK
| | - Loretta M Murphy
- School of Chemistry , Bangor University , Bangor , Gwynedd , Wales LL57 2UW , UK
| | - Richard W Strange
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
- Molecular Biophysics Group , Institute of Integrative Biology , Faculty of Health and Life Sciences , University of Liverpool , Liverpool , L69 7ZB , UK
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology , 131 Princess Street , Manchester M1 7DN , UK
| | - Colin R Andrew
- Department of Chemistry and Biochemistry , Eastern Oregon University , La Grande , Oregon 97850 , USA .
| | - Michael A Hough
- School of Biological Sciences , University of Essex , Wivenhoe Park , Colchester , Essex CO4 3SQ , UK .
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6
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Kruglik SG, Yoo BK, Lambry JC, Martin JL, Negrerie M. Structural changes and picosecond to second dynamics of cytochrome c in interaction with nitric oxide in ferrous and ferric redox states. Phys Chem Chem Phys 2017; 19:21317-21334. [DOI: 10.1039/c7cp02634j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
After dissociation NO rebinds to Cyt c in 10 ps whereas Met80 rebinds in 5 μs after NO release from Cyt c. A complete view of heme – NO dynamics within 12 orders of magnitude of time in Cyt c is presented.
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Affiliation(s)
- Sergei G. Kruglik
- Laboratoire Jean Perrin
- Sorbonne Universités
- UPMC Univ. Paris 06
- CNRS
- 75005 Paris
| | - Byung-Kuk Yoo
- Laboratoire d'Optique et Biosciences
- INSERM
- Ecole Polytechnique
- 91128 Palaiseau
- France
| | | | - Jean-Louis Martin
- Laboratoire d'Optique et Biosciences
- INSERM
- Ecole Polytechnique
- 91128 Palaiseau
- France
| | - Michel Negrerie
- Laboratoire d'Optique et Biosciences
- INSERM
- Ecole Polytechnique
- 91128 Palaiseau
- France
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7
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Andrew CR, Petrova ON, Lamarre I, Lambry JC, Rappaport F, Negrerie M. The Dynamics Behind the Affinity: Controlling Heme-Gas Affinity via Geminate Recombination and Heme Propionate Conformation in the NO Carrier Cytochrome c'. ACS Chem Biol 2016; 11:3191-3201. [PMID: 27709886 DOI: 10.1021/acschembio.6b00599] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nitric oxide (NO) sensors are heme proteins which may also bind CO and O2. Control of heme-gas affinity and their discrimination are achieved by the structural properties and reactivity of the heme and its distal and proximal environments, leading to several energy barriers. In the bacterial NO sensor cytochrome c' from Alcaligenes xylosoxidans (AXCP), the single Leu16Ala distal mutation boosts the affinity for gas ligands by a remarkable 106-108-fold, transforming AXCP from one of the lowest affinity gas binding proteins to one of the highest. Here, we report the dynamics of diatomics after photodissociation from wild type and L16A-AXCP over 12 orders of magnitude in time. For the L16A variant, the picosecond geminate rebinding of both CO and NO appears with an unprecedented 100% yield, and no exit of these ligands from protein to solvent could be observed. Molecular dynamic simulations saliently demonstrate that dissociated CO stays within 4 Å from Fe2+, in contrast to wild-type AXCP. The L16A mutation confers a heme propionate conformation and docking site which traps the diatomics, maximizing the probability of recombination and directly explaining the ultrahigh affinities for CO, NO, and O2. Overall, our results point to a novel mechanism for modulating heme-gas affinities in proteins.
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Affiliation(s)
- Colin R. Andrew
- Department
of Chemistry and Biochemistry, Eastern Oregon University, La Grande, Oregon 97850, United States
| | - Olga N. Petrova
- Laboratoire
d’Optique et Biosciences, INSERM, Ecole Polytechnique, 91128 Palaiseau, France
| | - Isabelle Lamarre
- Laboratoire
d’Optique et Biosciences, INSERM, Ecole Polytechnique, 91128 Palaiseau, France
| | - Jean-Christophe Lambry
- Laboratoire
d’Optique et Biosciences, INSERM, Ecole Polytechnique, 91128 Palaiseau, France
| | - Fabrice Rappaport
- Laboratoire
de Physiologie Membranaire et Moléculaire du Chloroplaste, CNRS, Université Pierre et Marie Curie, 75005 Paris, France
| | - Michel Negrerie
- Laboratoire
d’Optique et Biosciences, INSERM, Ecole Polytechnique, 91128 Palaiseau, France
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8
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Marciano O, Moskovitz Y, Hamza I, Ruthstein S. Histidine residues are important for preserving the structure and heme binding to the C. elegans HRG-3 heme-trafficking protein. J Biol Inorg Chem 2015; 20:1253-61. [PMID: 26531103 DOI: 10.1007/s00775-015-1304-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Accepted: 10/18/2015] [Indexed: 11/24/2022]
Abstract
C. elegans is a heme auxotroph that requires environmental heme for sustenance. As such, worms utilize HRG-3, a small heme-trafficking protein, to traffic heme from the intestine to extra-intestinal tissues and embryos. However, how HRG-3 binds and delivers heme remains unknown. In this study, we utilized electron paramagnetic resonance spectroscopy together with site-directed spin labeling, absorption spectroscopy, circular dichroism, and mutagenesis to gain structural and molecular insights into HRG-3. We showed that HRG-3 is a dimer, whereas H9 and H10 are significant residues that preserve a specific conformational state in the HRG-3 dimer. In the absence of H9 and H10, HRG-3 can still bind heme, although with a different affinity. Furthermore, the heme-binding site is closer to the N-termini than to the C-termini. Taken together, our results lay the groundwork for future mechanistic and structural studies of HRG-3 and inter-tissue heme trafficking in metazoans.
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Affiliation(s)
- Ortal Marciano
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, 5290002, Ramat-Gan, Israel
| | - Yoni Moskovitz
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, 5290002, Ramat-Gan, Israel
| | - Iqbal Hamza
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, 20742, USA.,Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, MD, 20742, USA
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences, Bar Ilan University, 5290002, Ramat-Gan, Israel.
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9
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Motion of proximal histidine and structural allosteric transition in soluble guanylate cyclase. Proc Natl Acad Sci U S A 2015; 112:E1697-704. [PMID: 25831539 DOI: 10.1073/pnas.1423098112] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
We investigated the changes of heme coordination in purified soluble guanylate cyclase (sGC) by time-resolved spectroscopy in a time range encompassing 11 orders of magnitude (from 1 ps to 0.2 s). After dissociation, NO either recombines geminately to the 4-coordinate (4c) heme (τG1 = 7.5 ps; 97 ± 1% of the population) or exits the heme pocket (3 ± 1%). The proximal His rebinds to the 4c heme with a 70-ps time constant. Then, NO is distributed in two approximately equal populations (1.5%). One geminately rebinds to the 5c heme (τG2 = 6.5 ns), whereas the other diffuses out to the solution, from where it rebinds bimolecularly (τ = 50 μs with [NO] = 200 μM) forming a 6c heme with a diffusion-limited rate constant of 2 × 10(8) M(-1)⋅s(-1). In both cases, the rebinding of NO induces the cleavage of the Fe-His bond that can be observed as an individual reaction step. Saliently, the time constant of bond cleavage differs depending on whether NO binds geminately or from solution (τ5C1 = 0.66 μs and τ5C2 = 10 ms, respectively). Because the same event occurs with rates separated by four orders of magnitude, this measurement implies that sGC is in different structural states in both cases, having different strain exerted on the Fe-His bond. We show here that this structural allosteric transition takes place in the range 1-50 μs. In this context, the detection of NO binding to the proximal side of sGC heme is discussed.
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10
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Hough MA, Andrew CR. Cytochromes c': Structure, Reactivity and Relevance to Haem-Based Gas Sensing. Adv Microb Physiol 2015; 67:1-84. [PMID: 26616515 DOI: 10.1016/bs.ampbs.2015.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cytochromes c' are a group of class IIa cytochromes with pentacoordinate haem centres and are found in photosynthetic, denitrifying and methanotrophic bacteria. Their function remains unclear, although roles in nitric oxide (NO) trafficking during denitrification or in cellular defence against nitrosoative stress have been proposed. Cytochromes c' are typically dimeric with each c-type haem-containing monomer folding as a four-α-helix bundle. Their hydrophobic and crowded distal sites impose severe restrictions on the binding of distal ligands, including diatomic gases. By contrast, NO binds to the proximal haem face in a similar manner to that of the eukaryotic NO sensor, soluble guanylate cyclase and bacterial analogues. In this review, we focus on how structural features of cytochromes c' influence haem spectroscopy and reactivity with NO, CO and O2. We also discuss the relevance of cytochrome c' to understanding the mechanisms of gas binding to haem-based sensor proteins.
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11
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Matsumura H, Hayashi T, Chakraborty S, Lu Y, Moënne-Loccoz P. The production of nitrous oxide by the heme/nonheme diiron center of engineered myoglobins (Fe(B)Mbs) proceeds through a trans-iron-nitrosyl dimer. J Am Chem Soc 2014; 136:2420-31. [PMID: 24432820 PMCID: PMC4004238 DOI: 10.1021/ja410542z] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Denitrifying NO reductases are transmembrane
protein complexes
that are evolutionarily related to heme/copper terminal oxidases.
They utilize a heme/nonheme diiron center to reduce two NO molecules
to N2O. Engineering a nonheme FeB site within
the heme distal pocket of sperm whale myoglobin has offered well-defined
diiron clusters for the investigation of the mechanism of NO reduction
in these unique active sites. In this study, we use FTIR spectroscopy
to monitor the production of N2O in solution and to show
that the presence of a distal FeBII is not sufficient
to produce the expected product. However, the addition of a glutamate
side chain peripheral to the diiron site allows for 50% of a productive
single-turnover reaction. Unproductive reactions are characterized
by resonance Raman spectroscopy as dinitrosyl complexes, where one
NO molecule is bound to the heme iron to form a five-coordinate low-spin
{FeNO}7 species with ν(FeNO)heme and ν(NO)heme at 522 and 1660 cm–1, and a second NO
molecule is bound to the nonheme FeB site with a ν(NO)FeB at 1755 cm–1. Stopped-flow UV–vis
absorption coupled with rapid-freeze-quench resonance Raman spectroscopy
provide a detailed map of the reaction coordinates leading to the
unproductive iron-nitrosyl dimer. Unexpectedly, NO binding to FeB is kinetically favored and occurs prior to the binding of
a second NO to the heme iron, leading to a (six-coordinate low-spin
heme-nitrosyl/FeB-nitrosyl) transient dinitrosyl complex
with characteristic ν(FeNO)heme at 570 ± 2 cm–1 and ν(NO)FeB at 1755 cm–1. Without the addition of a peripheral glutamate, the dinitrosyl
complex is converted to a dead-end product after the dissociation
of the proximal histidine of the heme iron, but the added peripheral
glutamate side chain in FeBMb2 lowers the rate of dissociation
of the promixal histidine which in turn allows the (six-coordinate
low-spin heme-nitrosyl/FeB-nitrosyl) transient dinitrosyl
complex to decay with production of N2O at a rate of 0.7
s–1 at 4 °C. Taken together, our results support
the proposed trans mechanism of NO reduction in NORs.
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Affiliation(s)
- Hirotoshi Matsumura
- Divison of Environmental & Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University , 3181 SW Sam Jackson Park Road, Portland, Oregon 97239-3098, United States
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12
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Nitric oxide-sensing H-NOX proteins govern bacterial communal behavior. Trends Biochem Sci 2013; 38:566-75. [PMID: 24113192 DOI: 10.1016/j.tibs.2013.08.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/26/2013] [Accepted: 08/27/2013] [Indexed: 11/22/2022]
Abstract
Heme-nitric oxide/oxygen binding (H-NOX) domains function as sensors for the gaseous signaling agent nitric oxide (NO) in eukaryotes and bacteria. Mammalian NO signaling is well characterized and involves the H-NOX domain of soluble guanylate cyclase. In bacteria, H-NOX proteins interact with bacterial signaling proteins in two-component signaling systems or in cyclic-di-GMP metabolism. Characterization of several downstream signaling processes has shown that bacterial H-NOX proteins share a common role in controlling important bacterial communal behaviors in response to NO. The H-NOX pathways regulate motility, biofilm formation, quorum sensing, and symbiosis. Here, we review the latest structural and mechanistic studies that have elucidated how H-NOX domains selectively bind NO and transduce ligand binding into conformational changes that modulate activity of signaling partners. Furthermore, we summarize the recent advances in understanding the physiological function and biochemical details of the H-NOX signaling pathways.
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13
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Ramos-Alvarez C, Yoo BK, Pietri R, Lamarre I, Martin JL, Lopez-Garriga J, Negrerie M. Reactivity and dynamics of H2S, NO, and O2 interacting with hemoglobins from Lucina pectinata. Biochemistry 2013; 52:7007-21. [PMID: 24040745 DOI: 10.1021/bi400745a] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hemoglobin HbI from the clam Lucina pectinata is involved in H2S transport, whereas homologous heme protein HbII/III is involved in O2 metabolism. Despite similar tertiary structures, HbI and HbII/III exhibit very different reactivity toward heme ligands H2S, O2, and NO. To investigate this reactivity at the heme level, we measured the dynamics of ligand interaction by time-resolved absorption spectroscopy in the picosecond to nanosecond time range. We demonstrated that H2S can be photodissociated from both ferric and ferrous HbI. H2S geminately rebinds to ferric and ferrous out-of-plane iron with time constants (τgem) of 12 and 165 ps, respectively, with very different proportions of photodissociated H2S exiting the protein (24% in ferric and 80% in ferrous HbI). The Gln(E7)His mutation considerably changes H2S dynamics in ferric HbI, indicating the role of Gln(E7) in controling H2S reactivity. In ferric HbI, the rate of diffusion of H2S from the solvent into the heme pocket (kentry) is 0.30 μM(-1) s(-1). For the HbII/III-O2 complex, we observed mainly a six-coordinate vibrationally excited heme-O2 complex with O2 still bound to the iron. This explains the low yield of O2 photodissociation and low koff from HbII/III, compared with those of HbI and Mb. Both isoforms behave very differently with regard to NO and O2 dynamics. Whereas the amplitude of geminate rebinding of O2 to HbI (38.5%) is similar to that of myoglobin (34.5%) in spite of different distal heme sites, it appears to be much larger for HbII/III (77%). The distal Tyr(B10) side chain present in HbII/III increases the energy barrier for ligand escape and participates in the stabilization of bound O2 and NO.
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Affiliation(s)
- Cacimar Ramos-Alvarez
- Department of Chemistry, University of Puerto Rico , Mayagüez Campus, Mayagüez 00680, Puerto Rico
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14
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Pietra F. Gates and Binding Pockets for Nitric Oxide with Cytochrome c′, According to Molecular Dynamics. Chem Biodivers 2013; 10:1574-88. [DOI: 10.1002/cbdv.201300164] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Indexed: 12/26/2022]
Affiliation(s)
- Francesco Pietra
- Accademia Lucchese di Scienze, Lettere e Arti, Classe di Scienze, Palazzo Ducale, Lucca I-55100 (phone/fax: +39-0583-417336).
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15
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Russell HJ, Hardman SJO, Heyes DJ, Hough MA, Greetham GM, Towrie M, Hay S, Scrutton NS. Modulation of ligand-heme reactivity by binding pocket residues demonstrated in cytochrome c' over the femtosecond-second temporal range. FEBS J 2013; 280:6070-82. [PMID: 24034856 PMCID: PMC4163637 DOI: 10.1111/febs.12526] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/05/2013] [Accepted: 09/10/2013] [Indexed: 12/27/2022]
Abstract
The ability of hemoproteins to discriminate between diatomic molecules, and the subsequent affinity for their chosen ligand, is fundamental to the existence of life. These processes are often controlled by precise structural arrangements in proteins, with heme pocket residues driving reactivity and specificity. One such protein is cytochrome c', which has the ability to bind nitric oxide (NO) and carbon monoxide (CO) on opposite faces of the heme, a property that is shared with soluble guanylate cycle. Like soluble guanylate cyclase, cytochrome c' also excludes O2 completely from the binding pocket. Previous studies have shown that the NO binding mechanism is regulated by a proximal arginine residue (R124) and a distal leucine residue (L16). Here, we have investigated the roles of these residues in maintaining the affinity for NO in the heme binding environment by using various time‐resolved spectroscopy techniques that span the entire femtosecond–second temporal range in the UV‐vis spectrum, and the femtosecond–nanosecond range by IR spectroscopy. Our findings indicate that the tightly regulated NO rebinding events following excitation in wild‐type cytochrome c' are affected in the R124A variant. In the R124A variant, vibrational and electronic changes extend continuously across all time scales (from fs–s), in contrast to wild‐type cytochrome c' and the L16A variant. Based on these findings, we propose a NO (re)binding mechanism for the R124A variant of cytochrome c' that is distinct from that in wild‐type cytochrome c'. In the wider context, these findings emphasize the importance of heme pocket architecture in maintaining the reactivity of hemoproteins towards their chosen ligand, and demonstrate the power of spectroscopic probes spanning a wide temporal range.
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Affiliation(s)
- Henry J Russell
- Faculty of Life Sciences, Manchester Institute of Biotechnology and Photon Science Institute, The University of Manchester, UK
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