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Rojas BL, Vazquez-Rivera E, Partch CL, Bradfield CA. Dimerization Rules of Mammalian PAS Proteins. J Mol Biol 2024; 436:168406. [PMID: 38109992 PMCID: PMC10922841 DOI: 10.1016/j.jmb.2023.168406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/11/2023] [Accepted: 12/13/2023] [Indexed: 12/20/2023]
Abstract
The PAS (PER, ARNT, SIM) protein family plays a vital role in mammalian biology and human disease. This analysis arose from an interest in the signaling mechanics by the Ah receptor (AHR) and the Ah receptor nuclear translocator (ARNT). After more than fifty years by studying this and related mammalian sensor systems, describing the role of PAS domains in signal transduction is still challenging. In this perspective, we attempt to interpret recent studies of mammalian PAS protein structure and consider how this new insight might explain how these domains are employed in human signal transduction with an eye towards developing strategies to target and engineer these molecules for a new generation of therapeutics. Our approach is to integrate our understanding of PAS protein history, cell biology, and molecular biology with recent structural discoveries to help explain the mechanics of mammalian PAS protein signaling. As a learning set, we focus on sequences and crystal structures of mammalian PAS protein dimers that can be visualized using readily available software.
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Affiliation(s)
- Brenda L Rojas
- Molecular and Environmental Toxicology Center, University of Wisconsin at Madison, USA
| | | | - Carrie L Partch
- Department of Chemistry and Biochemistry, University of California at Santa Cruz, USA
| | - Christopher A Bradfield
- Molecular and Environmental Toxicology Center, University of Wisconsin at Madison, USA; McArdle Laboratory for Cancer Research. University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA.
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2
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Montfort WR. Per-ARNT-Sim Domains in Nitric Oxide Signaling by Soluble Guanylyl Cyclase. J Mol Biol 2024; 436:168235. [PMID: 37572934 PMCID: PMC10858291 DOI: 10.1016/j.jmb.2023.168235] [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: 06/29/2023] [Revised: 08/01/2023] [Accepted: 08/04/2023] [Indexed: 08/14/2023]
Abstract
Nitric oxide (NO) regulates large swaths of animal physiology including wound healing, vasodilation, memory formation, odor detection, sexual function, and response to infectious disease. The primary NO receptor is soluble guanyly/guanylate cyclase (sGC), a dimeric protein of ∼150 kDa that detects NO through a ferrous heme, leading to a large change in conformation and enhanced production of cGMP from GTP. In humans, loss of sGC function contributes to multiple disease states, including cardiovascular disease and cancer, and is the target of a new class of drugs, sGC stimulators, now in clinical use. sGC evolved through the fusion of four ancient domains, a heme nitric oxide / oxygen (H-NOX) domain, a Per-ARNT-Sim (PAS) domain, a coiled coil, and a cyclase domain, with catalysis occurring at the interface of the two cyclase domains. In animals, the predominant dimer is the α1β1 heterodimer, with the α1 subunit formed through gene duplication of the β1 subunit. The PAS domain provides an extensive dimer interface that remains unchanged during sGC activation, acting as a core anchor. A large cleft formed at the PAS-PAS dimer interface tightly binds the N-terminal end of the coiled coil, keeping this region intact and unchanged while the rest of the coiled coil repacks, and the other domains reposition. This interface buries ∼3000 Å2 of monomer surface and includes highly conserved apolar and hydrogen bonding residues. Herein, we discuss the evolutionary history of sGC, describe the role of PAS domains in sGC function, and explore the regulatory factors affecting sGC function.
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Affiliation(s)
- William R Montfort
- Department of Chemistry & Biochemistry, University of Arizona, Tucson, AZ 85721, USA.
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3
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Jehle A, Garaschuk O. The Interplay between cGMP and Calcium Signaling in Alzheimer’s Disease. Int J Mol Sci 2022; 23:ijms23137048. [PMID: 35806059 PMCID: PMC9266933 DOI: 10.3390/ijms23137048] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 05/31/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Cyclic guanosine monophosphate (cGMP) is a ubiquitous second messenger and a key molecule in many important signaling cascades in the body and brain, including phototransduction, olfaction, vasodilation, and functional hyperemia. Additionally, cGMP is involved in long-term potentiation (LTP), a cellular correlate of learning and memory, and recent studies have identified the cGMP-increasing drug Sildenafil as a potential risk modifier in Alzheimer’s disease (AD). AD development is accompanied by a net increase in the expression of nitric oxide (NO) synthases but a decreased activity of soluble guanylate cyclases, so the exact sign and extent of AD-mediated imbalance remain unclear. Moreover, human patients and mouse models of the disease present with entangled deregulation of both cGMP and Ca2+ signaling, e.g., causing changes in cGMP-mediated Ca2+ release from the intracellular stores as well as Ca2+-mediated cGMP production. Still, the mechanisms governing such interplay are poorly understood. Here, we review the recent data on mechanisms underlying the brain cGMP signaling and its interconnection with Ca2+ signaling. We also discuss the recent evidence stressing the importance of such interplay for normal brain function as well as in Alzheimer’s disease.
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4
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Xia J, Hui N, Tian L, Liang C, Zhang J, Liu J, Wang J, Ren X, Xie X, Wang K. Development of vericiguat: The first soluble guanylate cyclase (sGC) stimulator launched for heart failure with reduced ejection fraction (HFrEF). Biomed Pharmacother 2022; 149:112894. [PMID: 35367763 DOI: 10.1016/j.biopha.2022.112894] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 03/23/2022] [Accepted: 03/25/2022] [Indexed: 11/02/2022] Open
Abstract
In recent years, with improvements in treatments for heart failure (HF), the survival period of patients has been extended. However, the emergence of some patients with repeated hospitalizations due to their worsening conditions and low survival rates followed. Currently, few drugs are available for such patients. Vericiguat was first drug approved for the treatment of symptomatic patients with chronic HF with reduced ejection fraction (HFrEF) to reduce the occurrence of worsening HF. This article provides comprehensive information about vericiguat in terms of drug design and development, structure-activity relationship (SAR), synthesis, pharmacological efficacy, and clinical practice. In addition, insights into the current vericiguat trials and treatments of HF are also discussed.
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Affiliation(s)
- Juan Xia
- Laboratory of Hematologic Diseases, Affiliated Hospital of Guangdong Medical University, Zhanjiang 524001, PR China.
| | - Nan Hui
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an 710021, PR China.
| | - Lei Tian
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an 710021, PR China.
| | - Chengyuan Liang
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an 710021, PR China.
| | - Jie Zhang
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an 710021, PR China.
| | - Jifang Liu
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an 710021, PR China.
| | - Jun Wang
- Faculty of Pharmacy, Shaanxi University of Science & Technology, Xi'an 710021, PR China; Key Laboratory of Traditional Chinese and Tibetan Medicine of Qinghai Province, Qinghai Provincial Drug Inspection and Testing Institute, Xining 810000, PR China.
| | - Xiaodong Ren
- Medical College, Guizhou University, Guiyang 550025, PR China.
| | - Xiaolin Xie
- Shaanxi Panlong Pharmaceutical Group Co., Ltd. Xi'an, 710025, PR China.
| | - Kun Wang
- Children's Center, the Affiliated Taian City Centeral Hospital of Qingdao University, Taian, Shandong, 271000, PR China.
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5
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Li J, Zhou Y, Lin YW, Tan X. A novel insight into the molecular mechanism of human soluble guanylyl cyclase focused on catalytic domain in living cells. Biochem Biophys Res Commun 2022; 604:51-56. [DOI: 10.1016/j.bbrc.2022.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 03/04/2022] [Indexed: 11/25/2022]
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6
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Lehnert N, Kim E, Dong HT, Harland JB, Hunt AP, Manickas EC, Oakley KM, Pham J, Reed GC, Alfaro VS. The Biologically Relevant Coordination Chemistry of Iron and Nitric Oxide: Electronic Structure and Reactivity. Chem Rev 2021; 121:14682-14905. [PMID: 34902255 DOI: 10.1021/acs.chemrev.1c00253] [Citation(s) in RCA: 90] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Nitric oxide (NO) is an important signaling molecule that is involved in a wide range of physiological and pathological events in biology. Metal coordination chemistry, especially with iron, is at the heart of many biological transformations involving NO. A series of heme proteins, nitric oxide synthases (NOS), soluble guanylate cyclase (sGC), and nitrophorins, are responsible for the biosynthesis, sensing, and transport of NO. Alternatively, NO can be generated from nitrite by heme- and copper-containing nitrite reductases (NIRs). The NO-bearing small molecules such as nitrosothiols and dinitrosyl iron complexes (DNICs) can serve as an alternative vehicle for NO storage and transport. Once NO is formed, the rich reaction chemistry of NO leads to a wide variety of biological activities including reduction of NO by heme or non-heme iron-containing NO reductases and protein post-translational modifications by DNICs. Much of our understanding of the reactivity of metal sites in biology with NO and the mechanisms of these transformations has come from the elucidation of the geometric and electronic structures and chemical reactivity of synthetic model systems, in synergy with biochemical and biophysical studies on the relevant proteins themselves. This review focuses on recent advancements from studies on proteins and model complexes that not only have improved our understanding of the biological roles of NO but also have provided foundations for biomedical research and for bio-inspired catalyst design in energy science.
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Affiliation(s)
- Nicolai Lehnert
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Eunsuk Kim
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Hai T Dong
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Jill B Harland
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Andrew P Hunt
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Elizabeth C Manickas
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Kady M Oakley
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - John Pham
- Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States
| | - Garrett C Reed
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
| | - Victor Sosa Alfaro
- Department of Chemistry and Department of Biophysics, University of Michigan, Ann Arbor, Michigan 48109-1055, United States
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7
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Phylogenetic Analysis with Prediction of Cofactor or Ligand Binding for Pseudomonas aeruginosa PAS and Cache Domains. Microbiol Spectr 2021; 9:e0102621. [PMID: 34937179 PMCID: PMC8694187 DOI: 10.1128/spectrum.01026-21] [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] [Indexed: 11/20/2022] Open
Abstract
PAS domains are omnipresent building blocks of multidomain proteins in all domains of life. Bacteria possess a variety of PAS domains in intracellular proteins and the related Cache domains in periplasmic or extracellular proteins. PAS and Cache domains are predominant in sensory systems, often carry cofactors or bind ligands, and serve as dimerization domains in protein association. To aid our understanding of the wide distribution of these domains, we analyzed the proteome of the opportunistic human pathogen Pseudomonas aeruginosa PAO1 in silico. The ability of this bacterium to survive under different environmental conditions, to switch between planktonic and sessile/biofilm lifestyle, or to evade stresses, notably involves c-di-GMP regulatory proteins or depends on sensory pathways involving multidomain proteins that possess PAS or Cache domains. Maximum likelihood phylogeny was used to group PAS and Cache domains on the basis of amino acid sequence. Conservation of cofactor- or ligand-coordinating amino acids aided by structure-based comparison was used to inform function. The resulting classification presented here includes PAS domains that are candidate binders of carboxylic acids, amino acids, fatty acids, flavin adenine dinucleotide (FAD), 4-hydroxycinnamic acid, and heme. These predictions are put in context to previously described phenotypic data, often generated from deletion mutants. The analysis predicts novel functions for sensory proteins and sheds light on functional diversification in a large set of proteins with similar architecture. IMPORTANCE To adjust to a variety of life conditions, bacteria typically use multidomain proteins, where the modular structure allows functional differentiation. Proteins responding to environmental cues and regulating physiological responses are found in chemotaxis pathways that respond to a wide range of stimuli to affect movement. Environmental cues also regulate intracellular levels of cyclic-di-GMP, a universal bacterial secondary messenger that is a key determinant of bacterial lifestyle and virulence. We study Pseudomonas aeruginosa, an organism known to colonize a broad range of environments that can switch lifestyle between the sessile biofilm and the planktonic swimming form. We have investigated the PAS and Cache domains, of which we identified 101 in 70 Pseudomonas aeruginosa PAO1 proteins, and have grouped these by phylogeny with domains of known structure. The resulting data set integrates sequence analysis and structure prediction to infer ligand or cofactor binding. With this data set, functional predictions for PAS and Cache domain-containing proteins are made.
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8
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Wittenborn EC, Marletta MA. Structural Perspectives on the Mechanism of Soluble Guanylate Cyclase Activation. Int J Mol Sci 2021; 22:ijms22115439. [PMID: 34064029 PMCID: PMC8196705 DOI: 10.3390/ijms22115439] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 11/30/2022] Open
Abstract
The enzyme soluble guanylate cyclase (sGC) is the prototypical nitric oxide (NO) receptor in humans and other higher eukaryotes and is responsible for transducing the initial NO signal to the secondary messenger cyclic guanosine monophosphate (cGMP). Generation of cGMP in turn leads to diverse physiological effects in the cardiopulmonary, vascular, and neurological systems. Given these important downstream effects, sGC has been biochemically characterized in great detail in the four decades since its discovery. Structures of full-length sGC, however, have proven elusive until very recently. In 2019, advances in single particle cryo–electron microscopy (cryo-EM) enabled visualization of full-length sGC for the first time. This review will summarize insights revealed by the structures of sGC in the unactivated and activated states and discuss their implications in the mechanism of sGC activation.
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9
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Friebe A, Englert N. NO-sensitive guanylyl cyclase in the lung. Br J Pharmacol 2020; 179:2328-2343. [PMID: 33332689 DOI: 10.1111/bph.15345] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 12/21/2022] Open
Abstract
In the late 1960s, several labatories identified guanylyl cyclase (GC) as the cGMP-producing enzyme. Subsequently, two different types of GC were described that differed in their cellular localization. Primarily found in the cytosol, nitric oxide (NO)-sensitive guanylyl cyclase (NO-GC) acts as receptor for the signalling molecule NO, in contrast the membrane-bound isoenzyme is activated by natriuretic peptides. The lung compared with other tissues exhibits the highest expression of NO-GC. The enzyme has been purified from lung for biochemical analysis. Although expressed in smooth muscle cells (SMCs) and in pericytes, the function of NO-GC in lung, especially in pericytes, is still not fully elucidated. However, pharmacological compounds that target NO-GC are available and have been implemented for the therapy of pulmonary arterial hypertension. In addition, NO-GC has been suggested as drug target for the therapy of asthma, acute respiratory distress syndrome and pulmonary fibrosis.
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Affiliation(s)
- Andreas Friebe
- Physiological Institute, Julius Maximilian University of Würzburg, Würzburg, Germany
| | - Nils Englert
- Physiological Institute, Julius Maximilian University of Würzburg, Würzburg, Germany
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10
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Tyrosine 135 of the β1 subunit as binding site of BAY-543: Importance of the Y-x-S-x-R motif for binding and activation by sGC activator drugs. Eur J Pharmacol 2020; 881:173203. [DOI: 10.1016/j.ejphar.2020.173203] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 11/22/2022]
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11
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Childers KC, Yao XQ, Giannakoulias S, Amason J, Hamelberg D, Garcin ED. Synergistic mutations in soluble guanylyl cyclase (sGC) reveal a key role for interfacial regions in the sGC activation mechanism. J Biol Chem 2019; 294:18451-18464. [PMID: 31645439 PMCID: PMC6885636 DOI: 10.1074/jbc.ra119.011010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 10/17/2019] [Indexed: 01/20/2023] Open
Abstract
Soluble guanylyl cyclase (sGC) is the main receptor for nitric oxide (NO) and a central component of the NO-cGMP pathway, critical to cardiovascular function. NO binding to the N-terminal sensor domain in sGC enhances the cyclase activity of the C-terminal catalytic domain. Our understanding of the structural elements regulating this signaling cascade is limited, hindering structure-based drug design efforts that target sGC to improve the management of cardiovascular diseases. Conformational changes are thought to propagate the NO-binding signal throughout the entire sGC heterodimer, via its coiled-coil domain, to reorient the catalytic domain into an active conformation. To identify the structural elements involved in this signal transduction cascade, here we optimized a cGMP-based luciferase assay that reports on heterologous sGC activity in Escherichia coli and identified several mutations that activate sGC. These mutations resided in the dorsal flaps, dimer interface, and GTP-binding regions of the catalytic domain. Combinations of mutations from these different elements synergized, resulting in even greater activity and indicating a complex cross-talk among these regions. Molecular dynamics simulations further revealed conformational changes underlying the functional impact of these mutations. We propose that the interfacial residues play a central role in the sGC activation mechanism by coupling the coiled-coil domain to the active site via a series of hot spots. Our results provide new mechanistic insights not only into the molecular pathway for sGC activation but also for other members of the larger nucleotidyl cyclase family.
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Affiliation(s)
- Kenneth C Childers
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250
| | - Xin-Qiu Yao
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965
| | - Sam Giannakoulias
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250
| | - Joshua Amason
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250.
| | - Donald Hamelberg
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30302-3965
| | - Elsa D Garcin
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County, Baltimore, Maryland 21250.
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12
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Horst BG, Yokom AL, Rosenberg DJ, Morris KL, Hammel M, Hurley JH, Marletta MA. Allosteric activation of the nitric oxide receptor soluble guanylate cyclase mapped by cryo-electron microscopy. eLife 2019; 8:50634. [PMID: 31566566 PMCID: PMC6839917 DOI: 10.7554/elife.50634] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 09/27/2019] [Indexed: 12/14/2022] Open
Abstract
Soluble guanylate cyclase (sGC) is the primary receptor for nitric oxide (NO) in mammalian nitric oxide signaling. We determined structures of full-length Manduca sexta sGC in both inactive and active states using cryo-electron microscopy. NO and the sGC-specific stimulator YC-1 induce a 71° rotation of the heme-binding β H-NOX and PAS domains. Repositioning of the β H-NOX domain leads to a straightening of the coiled-coil domains, which, in turn, use the motion to move the catalytic domains into an active conformation. YC-1 binds directly between the β H-NOX domain and the two CC domains. The structural elongation of the particle observed in cryo-EM was corroborated in solution using small angle X-ray scattering (SAXS). These structures delineate the endpoints of the allosteric transition responsible for the major cyclic GMP-dependent physiological effects of NO. In humans and other animals, as the heart pumps blood around the body, the blood exerts pressure on the walls of the blood vessels, much like water flowing through a hose. Our blood pressure naturally varies over the day, generally increasing when we are active and decreasing when we rest. However, if blood pressure remains high for extended periods of time it can lead to heart attacks, strokes and other serious health conditions. In 2013, a new drug known as Adempas was approved to treat high blood pressure in the lungs. This drug helps a signaling molecule in the body called nitric oxide to activate an enzyme that widens blood vessels and in turn lower blood pressure. Previous studies have found that the enzyme – called soluble guanylate cyclase (sGC) – contains several distinct domains and that nitric oxide binds to a domain known as β H-NOX. However, it was not clear how β H-NOX and the other three domains fit together to make the three-dimensional structure of the enzyme, or how nitric oxide and Adempas activate it. To address this question, Horst, Yokom et al. used a technique called cryo-electron microscopy to determine the three-dimensional structures of the inactive and active forms of a soluble guanylate cyclase from a moth known as Manduca sexta. To produce the active form of the enzyme, soluble guanylate cyclase was incubated with both nitric oxide and a molecule called YC-1 that works in similar way to Adempas. The structures revealed that nitric oxide and YC-1 caused β H-NOX and another domain to rotate by 71. This in turn caused the remaining two domains – known as the coiled-coil domains – to change shape, and all of these movements together led to the activated enzyme. The structures also revealed that YC-1 bound to a site on the enzyme between β H-NOX and the coiled-coil domains. Understanding how a drug for a particular condition works makes it much easier to develop new drugs that are more effective at treating the same condition or are tailored to treat other diseases. Therefore, these findings will allow pharmaceutical companies and other organizations to develop new drugs for high blood pressure and other cardiovascular diseases in a much more precise way.
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Affiliation(s)
- Benjamin G Horst
- Department of Chemistry, University of California, Berkeley, Berkeley, United States
| | - Adam L Yokom
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Graduate Group in Biophysics, University of California, Berkeley, Berkeley, United States
| | - Daniel J Rosenberg
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
| | - Kyle L Morris
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Graduate Group in Biophysics, University of California, Berkeley, Berkeley, United States
| | - Michal Hammel
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, United States
| | - James H Hurley
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Graduate Group in Biophysics, University of California, Berkeley, Berkeley, United States.,Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, United States.,California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, United States
| | - Michael A Marletta
- Department of Chemistry, University of California, Berkeley, Berkeley, United States.,Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.,Graduate Group in Biophysics, University of California, Berkeley, Berkeley, United States
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13
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Structural insights into the mechanism of human soluble guanylate cyclase. Nature 2019; 574:206-210. [PMID: 31514202 DOI: 10.1038/s41586-019-1584-6] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/03/2019] [Indexed: 01/01/2023]
Abstract
Soluble guanylate cyclase (sGC) is the primary sensor of nitric oxide. It has a central role in nitric oxide signalling and has been implicated in many essential physiological processes and disease conditions. The binding of nitric oxide boosts the enzymatic activity of sGC. However, the mechanism by which nitric oxide activates the enzyme is unclear. Here we report the cryo-electron microscopy structures of the human sGCα1β1 heterodimer in different functional states. These structures revealed that the transducer module bridges the nitric oxide sensor module and the catalytic module. Binding of nitric oxide to the β1 haem-nitric oxide and oxygen binding (H-NOX) domain triggers the structural rearrangement of the sensor module and a conformational switch of the transducer module from bending to straightening. The resulting movement of the N termini of the catalytic domains drives structural changes within the catalytic module, which in turn boost the enzymatic activity of sGC.
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14
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Weichsel A, Kievenaar JA, Curry R, Croft JT, Montfort WR. Instability in a coiled-coil signaling helix is conserved for signal transduction in soluble guanylyl cyclase. Protein Sci 2019; 28:1830-1839. [PMID: 31411784 DOI: 10.1002/pro.3707] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 08/10/2019] [Accepted: 08/12/2019] [Indexed: 01/01/2023]
Abstract
How nitric oxide (NO) activates its primary receptor, α1/β1 soluble guanylyl cyclase (sGC or GC-1), remains unknown. Likewise, how stimulatory compounds enhance sGC activity is poorly understood, hampering development of new treatments for cardiovascular disease. NO binding to ferrous heme near the N-terminus in sGC activates cyclase activity near the C-terminus, yielding cGMP production and physiological response. CO binding can also stimulate sGC, but only weakly in the absence of stimulatory small-molecule compounds, which together lead to full activation. How ligand binding enhances catalysis, however, has yet to be discovered. Here, using a truncated version of sGC from Manduca sexta, we demonstrate that the central coiled-coil domain, the most highly conserved region of the ~150,000 Da protein, not only provides stability to the heterodimer but is also conformationally active in signal transduction. Sequence conservation in the coiled coil includes the expected heptad-repeating pattern for coiled-coil motifs, but also invariant positions that disfavor coiled-coil stability. Full-length coiled coil dampens CO affinity for heme, while shortening of the coiled coil leads to enhanced CO binding. Introducing double mutation αE447L/βE377L, predicted to replace two destabilizing glutamates with leucines, lowers CO binding affinity while increasing overall protein stability. Likewise, introduction of a disulfide bond into the coiled coil results in reduced CO affinity. Taken together, we demonstrate that the heme domain is greatly influenced by coiled-coil conformation, suggesting communication between heme and catalytic domains is through the coiled coil. Highly conserved structural imperfections in the coiled coil provide needed flexibility for signal transduction.
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Affiliation(s)
- Andrzej Weichsel
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - Jessica A Kievenaar
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - Roslyn Curry
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - Jacob T Croft
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
| | - William R Montfort
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona
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15
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Dai Y, Schlanger S, Haque MM, Misra S, Stuehr DJ. Heat shock protein 90 regulates soluble guanylyl cyclase maturation by a dual mechanism. J Biol Chem 2019; 294:12880-12891. [PMID: 31311859 DOI: 10.1074/jbc.ra119.009016] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 06/28/2019] [Indexed: 01/07/2023] Open
Abstract
The enzyme soluble guanylyl cyclase (sGC) is a heterodimer composed of an α subunit and a heme-containing β subunit. It participates in signaling by generating cGMP in response to nitric oxide (NO). Heme insertion into the β1 subunit of sGC (sGCβ) is critical for function, and heat shock protein 90 (HSP90) associates with heme-free sGCβ (apo-sGCβ) to drive its heme insertion. Here, we tested the accuracy and relevance of a modeled apo-sGCβ-HSP90 complex by constructing sGCβ variants predicted to have an impaired interaction with HSP90. Using site-directed mutagenesis, purified recombinant proteins, mammalian cell expression, and fluorescence approaches, we found that (i) three regions in apo-sGCβ predicted by the model mediate direct complex formation with HSP90 both in vitro and in mammalian cells; (ii) such HSP90 complex formation directly correlates with the extent of heme insertion into apo-sGCβ and with cyclase activity; and (iii) apo-sGCβ mutants possessing an HSP90-binding defect instead bind to sGCα in cells and form inactive, heme-free sGC heterodimers. Our findings uncover the molecular features of the cellular apo-sGCβ-HSP90 complex and reveal its dual importance in enabling heme insertion while preventing inactive heterodimer formation during sGC maturation.
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Affiliation(s)
- Yue Dai
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Simon Schlanger
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Mohammad Mahfuzul Haque
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
| | - Saurav Misra
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506
| | - Dennis J Stuehr
- Department of Inflammation and Immunity, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195.
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16
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Khalid RR, Maryam A, Fadouloglou VE, Siddiqi AR, Zhang Y. Cryo-EM density map fitting driven in-silico structure of human soluble guanylate cyclase (hsGC) reveals functional aspects of inter-domain cross talk upon NO binding. J Mol Graph Model 2019; 90:109-119. [PMID: 31055154 PMCID: PMC7956049 DOI: 10.1016/j.jmgm.2019.04.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/05/2019] [Accepted: 04/17/2019] [Indexed: 01/19/2023]
Abstract
The human soluble Guanylate Cyclase (hsGC) is a heterodimeric heme-containing enzyme which regulates many important physiological processes. In eukaryotes, hsGC is the only known receptor for nitric oxide (NO) signaling. Improper NO signaling results in various disease conditions such as neurodegeneration, hypertension, stroke and erectile dysfunction. To understand the mechanisms of these diseases, structure determination of the hsGC dimer complex is crucial. However, so far all the attempts for the experimental structure determination of the protein were unsuccessful. The current study explores the possibility to model the quaternary structure of hsGC using a hybrid approach that combines state-of-the-art protein structure prediction tools with cryo-EM experimental data. The resultant 3D model shows close consistency with structural and functional insights extracted from biochemistry experiment data. Overall, the atomic-level complex structure determination of hsGC helps to unveil the inter-domain communication upon NO binding, which should be of important usefulness for elucidating the biological function of this important enzyme and for developing new treatments against the hsGC associated human diseases.
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Affiliation(s)
- Rana Rehan Khalid
- Department of Biosciences, COMSATS University, Islamabad, 45550, Pakistan; Department of Biostatistics and Medical Informatics, Acibadem Universitesi, Istanbul, 34752, Turkey; Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2218, USA.
| | - Arooma Maryam
- Department of Biosciences, COMSATS University, Islamabad, 45550, Pakistan; Department of Pharmaceutical Chemistry, Biruni Universitesi, Istanbul, 34010, Turkey.
| | - Vasiliki E Fadouloglou
- Department of Molecular Biology and Genetics, Democritus University of Thrace, University Campus, Alexandroupolis, 68100, Greece.
| | - Abdul Rauf Siddiqi
- Department of Biosciences, COMSATS University, Islamabad, 45550, Pakistan.
| | - Yang Zhang
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109-2218, USA.
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17
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Sömmer A, Behrends S. Methods to investigate structure and activation dynamics of GC-1/GC-2. Nitric Oxide 2018; 78:S1089-8603(17)30348-8. [PMID: 29705716 DOI: 10.1016/j.niox.2018.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 04/19/2018] [Accepted: 04/23/2018] [Indexed: 12/18/2022]
Abstract
Soluble guanylyl cyclase (sGC) is a heterodimeric enzyme consisting of one α and one β subunit. The α1β1 (GC-1) and α2β1 (GC-2) heterodimers are important for NO signaling in humans and catalyse the conversion from GTP to cGMP. Each sGC subunit consists of four domains. Several crystal structures of the isolated domains are available. However, crystals of full-length sGC have failed to materialise. In consequence, the detailed three dimensional structure of sGC remains unknown to date. Different techniques including stopped-flow spectroscopy, Förster-resonance energy transfer, direct fluorescence, analytical ultracentrifugation, chemical cross-linking, small-angle X-ray scattering, electron microscopy, hydrogen-deuterium exchange and protein thermal shift assays, were used to collect indirect information. Taken together, this circumstantial evidence from different groups brings forth a plausible model of sGC domain arrangement, spatial orientation and dynamic rearrangement upon activation. For analysis of the active conformation the stable binding mode of sGC activators has a significant methodological advantage over the transient, elusive, complex and highly concentration dependent effects of NO in many applications. The methods used and the results obtained are reviewed and discussed in this article.
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Affiliation(s)
- Anne Sömmer
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig - Institute of Technology, Germany.
| | - Sönke Behrends
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig - Institute of Technology, Germany.
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18
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Childers KC, Garcin ED. Structure/function of the soluble guanylyl cyclase catalytic domain. Nitric Oxide 2018; 77:53-64. [PMID: 29702251 PMCID: PMC6005667 DOI: 10.1016/j.niox.2018.04.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 02/06/2023]
Abstract
Soluble guanylyl cyclase (GC-1) is the primary receptor of nitric oxide (NO) in smooth muscle cells and maintains vascular function by inducing vasorelaxation in nearby blood vessels. GC-1 converts guanosine 5′-triphosphate (GTP) into cyclic guanosine 3′,5′-monophosphate (cGMP), which acts as a second messenger to improve blood flow. While much work has been done to characterize this pathway, we lack a mechanistic understanding of how NO binding to the heme domain leads to a large increase in activity at the C-terminal catalytic domain. Recent structural evidence and activity measurements from multiple groups have revealed a low-activity cyclase domain that requires additional GC-1 domains to promote a catalytically-competent conformation. How the catalytic domain structurally transitions into the active conformation requires further characterization. This review focuses on structure/function studies of the GC-1 catalytic domain and recent advances various groups have made in understanding how catalytic activity is regulated including small molecules interactions, Cys-S-NO modifications and potential interactions with the NO-sensor domain and other proteins.
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Affiliation(s)
- Kenneth C Childers
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, Baltimore, USA
| | - Elsa D Garcin
- University of Maryland Baltimore County, Department of Chemistry and Biochemistry, Baltimore, USA.
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19
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Horst BG, Marletta MA. Physiological activation and deactivation of soluble guanylate cyclase. Nitric Oxide 2018; 77:65-74. [PMID: 29704567 DOI: 10.1016/j.niox.2018.04.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 04/23/2018] [Accepted: 04/23/2018] [Indexed: 01/24/2023]
Abstract
Soluble guanylate cyclase (sGC) is responsible for transducing the gaseous signaling molecule nitric oxide (NO) into the ubiquitous secondary signaling messenger cyclic guanosine monophosphate in eukaryotic organisms. sGC is exquisitely tuned to respond to low levels of NO, allowing cells to respond to non-toxic levels of NO. In this review, the structure of sGC is discussed in the context of sGC activation and deactivation. The sequence of events in the activation pathway are described into a comprehensive model of in vivo sGC activation as elucidated both from studies with purified enzyme and those done in cells. This model is then used to discuss the deactivation of sGC, as well as the molecular mechanisms of pathophysiological deactivation.
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Affiliation(s)
- Benjamin G Horst
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
| | - Michael A Marletta
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA; Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA.
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20
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Sömmer A, Behrends S. Synergistic stabilisation of NOsGC by cinaciguat and non-hydrolysable nucleotides: Evidence for sGC activator-induced communication between the heme-binding and catalytic domains. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:702-711. [PMID: 29653192 DOI: 10.1016/j.bbapap.2018.03.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 03/16/2018] [Accepted: 03/31/2018] [Indexed: 11/29/2022]
Abstract
Nitric oxide sensitive guanylyl cyclase (NOsGC) is a heterodimeric enzyme consisting of one α and one β subunit. Each subunit consists of four domains: the N-terminal heme-nitric oxide oxygen binding (HNOX) domain, a PAS domain, a coiled-coil domain and the C-terminal catalytic domain. Upon activation by the endogenous ligand NO or activating drugs, NOsGC catalyses the conversion of GTP to cGMP. Although several crystal structures of the isolated domains are known, the structure of the full-length enzyme and the interdomain conformational changes during activation remain unsolved to date. In the current study, we performed protein thermal shift assays of purified NOsGC to identify discrete conformational states amenable to further analysis e.g. by crystallisation. A non-hydrolysable substrate analogue binding to the catalytic domain led to a subtle change in melting temperature. An activator drug binding to the HNOX domain led to a small increase. However, the combination of substrate analogue and activator drug led to a marked synergistic increase from 51 °C to 60 °C. This suggests reciprocal communication between HNOX domain and catalytic domain and formation of a stable activated conformation amenable to further biophysical characterization.
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Affiliation(s)
- Anne Sömmer
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig - Institute of Technology, Germany.
| | - Sönke Behrends
- Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig - Institute of Technology, Germany.
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21
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Rojas-Pirela M, Rigden DJ, Michels PA, Cáceres AJ, Concepción JL, Quiñones W. Structure and function of Per-ARNT-Sim domains and their possible role in the life-cycle biology of Trypanosoma cruzi. Mol Biochem Parasitol 2017; 219:52-66. [PMID: 29133150 DOI: 10.1016/j.molbiopara.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 10/12/2017] [Accepted: 11/02/2017] [Indexed: 02/07/2023]
Abstract
Per-ARNT-Sim (PAS) domains of proteins play important roles as modules for signalling and cellular regulation processes in widely diverse organisms such as Archaea, Bacteria, protists, plants, yeasts, insects and vertebrates. These domains are present in many proteins where they are used as sensors of stimuli and modules for protein interactions. Characteristically, they can bind a broad spectrum of molecules. Such binding causes the domain to trigger a specific cellular response or to make the protein containing the domain susceptible to responding to additional physical or chemical signals. Different PAS proteins have the ability to sense redox potential, light, oxygen, energy levels, carboxylic acids, fatty acids and several other stimuli. Such proteins have been found to be involved in cellular processes such as development, virulence, sporulation, adaptation to hypoxia, circadian cycle, metabolism and gene regulation and expression. Our analysis of the genome of different kinetoplastid species revealed the presence of PAS domains also in different predicted kinases from these protists. Open-reading frames coding for these PAS-kinases are unusually large. In addition, the products of these genes appear to contain in their structure combinations of domains uncommon in other eukaryotes. The physiological significance of PAS domains in these parasites, specifically in Trypanosoma cruzi, is discussed.
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Affiliation(s)
- Maura Rojas-Pirela
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Daniel J Rigden
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, United Kingdom
| | - Paul A Michels
- Centre for Immunity, Infection and Evolution and Centre for Translational and Chemical Biology, School of Biological Sciences, The University of Edinburgh, The King's Buildings, Edinburgh EH9 3FL, Scotland, United Kingdom
| | - Ana J Cáceres
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Juan Luis Concepción
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela
| | - Wilfredo Quiñones
- Laboratorio de Enzimología de Parásitos, Departamento de Biología, Facultad de Ciencias, Universidad de Los Andes, Mérida 5101, Venezuela.
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22
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Probing the Molecular Mechanism of Human Soluble Guanylate Cyclase Activation by NO in vitro and in vivo. Sci Rep 2017; 7:43112. [PMID: 28230071 PMCID: PMC5322342 DOI: 10.1038/srep43112] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 01/19/2017] [Indexed: 11/12/2022] Open
Abstract
Soluble guanylate cyclase (sGC) is a heme-containing metalloprotein in NO-sGC-cGMP signaling. NO binds to the heme of sGC to catalyze the synthesis of the second messenger cGMP, which plays a critical role in several physiological processes. However, the molecular mechanism for sGC to mediate the NO signaling remains unclear. Here fluorophore FlAsH-EDT2 and fluorescent proteins were employed to study the NO-induced sGC activation. FlAsH-EDT2 labeling study revealed that NO binding to the H-NOX domain of sGC increased the distance between H-NOX and PAS domain and the separation between H-NOX and coiled-coil domain. The heme pocket conformation changed from “closed” to “open” upon NO binding. In addition, the NO-induced conformational change of sGC was firstly investigated in vivo through fluorescence lifetime imaging microscopy. The results both in vitro and in vivo indicated the conformational change of the catalytic domain of sGC from “open” to “closed” upon NO binding. NO binding to the heme of H-NOX domain caused breaking of Fe-N coordination bond, initiated the domain moving and conformational change, induced the allosteric effect of sGC to trigger the NO-signaling from H-NOX via PAS & coiled-coil to the catalytic domain, and ultimately stimulates the cyclase activity of sGC.
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23
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Drug discovery targeting heme-based sensors and their coupled activities. J Inorg Biochem 2017; 167:12-20. [DOI: 10.1016/j.jinorgbio.2016.11.022] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 11/08/2016] [Accepted: 11/16/2016] [Indexed: 01/10/2023]
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24
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Montfort WR, Wales JA, Weichsel A. Structure and Activation of Soluble Guanylyl Cyclase, the Nitric Oxide Sensor. Antioxid Redox Signal 2017; 26:107-121. [PMID: 26979942 PMCID: PMC5240008 DOI: 10.1089/ars.2016.6693] [Citation(s) in RCA: 91] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
SIGNIFICANCE Soluble guanylyl/guanylate cyclase (sGC) is the primary receptor for nitric oxide (NO) and is central to the physiology of blood pressure regulation, wound healing, memory formation, and other key physiological activities. sGC is increasingly implicated in disease and is targeted by novel therapeutic compounds. The protein displays a rich evolutionary history and a fascinating signal transduction mechanism, with NO binding to an N-terminal heme-containing domain, which activates the C-terminal cyclase domains. Recent Advances: Crystal structures of individual sGC domains or their bacterial homologues coupled with small-angle x-ray scattering, electron microscopy, chemical cross-linking, and Förster resonance energy transfer measurements are yielding insight into the overall structure for sGC, which is elongated and likely quite dynamic. Transient kinetic measurements reveal a role for individual domains in lowering NO affinity for heme. New sGC stimulatory drugs are now in the clinic and appear to function through binding near or directly to the sGC heme domain, relieving inhibitory contacts with other domains. New sGC-activating drugs show promise for recovering oxidized sGC in diseases with high inflammation by replacing lost heme. CRITICAL ISSUES Despite the many recent advances, sGC regulation, NO activation, and mechanisms of drug binding remain unclear. Here, we describe the molecular evolution of sGC, new molecular models, and the linked equilibria between sGC NO binding, drug binding, and catalytic activity. FUTURE DIRECTIONS Recent results and ongoing studies lay the foundation for a complete understanding of structure and mechanism, and they open the door for new drug discovery targeting sGC. Antioxid. Redox Signal. 26, 107-121.
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Affiliation(s)
- William R Montfort
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona
| | - Jessica A Wales
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona
| | - Andrzej Weichsel
- Department of Chemistry and Biochemistry, University of Arizona , Tucson, Arizona
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25
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Vijayaraghavan J, Kramp K, Harris ME, van den Akker F. Inhibition of soluble guanylyl cyclase by small molecules targeting the catalytic domain. FEBS Lett 2016; 590:3669-3680. [PMID: 27654641 DOI: 10.1002/1873-3468.12427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/29/2016] [Accepted: 09/09/2016] [Indexed: 12/23/2022]
Abstract
Soluble guanylyl cyclase (sGC) plays a crucial role in cyclic nucleotide signaling that regulates numerous important physiological processes. To identify new sGC inhibitors that may prevent the formation of the active catalytic domain conformation, we carried out an in silico docking screen targeting a 'backside pocket' of the inactive sGC catalytic domain structure. Compounds 1 and 2 were discovered to inhibit sGC even at high/saturating nitric oxide concentrations. Both compounds also inhibit the BAY 58-2667-activated sGC as well as BAY 41-2272-stimulated sGC activity. Additional biochemical analyses showed that compound 2 also inhibits the isolated catalytic domain, thus demonstrating functional binding to this domain. Both compounds have micromolar affinity for sGC and are potential leads to develop more potent sGC inhibitors.
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Affiliation(s)
| | - Kristopher Kramp
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Michael E Harris
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Focco van den Akker
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH, USA.
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26
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Pan J, Zhang X, Yuan H, Xu Q, Zhang H, Zhou Y, Huang ZX, Tan X. The molecular mechanism of heme loss from oxidized soluble guanylate cyclase induced by conformational change. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2016; 1864:488-500. [PMID: 26876536 DOI: 10.1016/j.bbapap.2016.02.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/05/2016] [Accepted: 02/10/2016] [Indexed: 11/25/2022]
Abstract
Heme oxidation and loss of soluble guanylate cyclase (sGC) is thought to be an important contributor to the development of cardiovascular diseases. Nevertheless, it remains unknown why the heme loses readily in oxidized sGC. In the current study, the conformational change of sGC upon heme oxidation by ODQ was studied based on the fluorescence resonance energy transfer (FRET) between the heme and a fluorophore fluorescein arsenical helix binder (FlAsH-EDT2) labeled at different domains of sGC β1. This study provides an opportunity to monitor the domain movement of sGC relative to the heme. The results indicated that heme oxidation by ODQ in truncated sCC induced the heme-associated αF helix moving away from the heme, the Per/Arnt/Sim domain (PAS) domain moving closer to the heme, but led the helical domain going further from the heme. We proposed that the synergistic effect of these conformational changes of the discrete region upon heme oxidation forces the heme pocket open, and subsequent heme loss readily. Furthermore, the kinetic studies suggested that the heme oxidation was a fast process and the conformational change was a relatively slow process. The kinetics of heme loss from oxidized sGC was monitored by a new method based on the heme group de-quenching the fluorescence of FlAsH-EDT2.
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Affiliation(s)
- Jie Pan
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China
| | - Xiaoxue Zhang
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China
| | - Hong Yuan
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China
| | - Qiming Xu
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, China
| | - Huijuan Zhang
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China
| | - Yajun Zhou
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China
| | - Zhong-Xian Huang
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China
| | - Xiangshi Tan
- Department of Chemistry & Shanghai Key laboratory of Chemical Biology for Protein Science, Fudan University, Shanghai 200433, China; Institutes of Biomedical Sciences, Fudan University, Shanghai 200433, China.
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27
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Shimizu T, Huang D, Yan F, Stranava M, Bartosova M, Fojtíková V, Martínková M. Gaseous O2, NO, and CO in signal transduction: structure and function relationships of heme-based gas sensors and heme-redox sensors. Chem Rev 2015; 115:6491-533. [PMID: 26021768 DOI: 10.1021/acs.chemrev.5b00018] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Toru Shimizu
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
- §Research Center for Compact Chemical System, National Institute of Advanced Industrial Science and Technology (AIST), Sendai 983-8551, Japan
| | - Dongyang Huang
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Fang Yan
- †Department of Cell Biology and Genetics and Key Laboratory of Molecular Biology in High Cancer Incidence Coastal Chaoshan Area of Guangdong Higher Education Institutes, Shantou University Medical College, Shantou, Guangdong 515041, China
| | - Martin Stranava
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Martina Bartosova
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Veronika Fojtíková
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
| | - Markéta Martínková
- ‡Department of Biochemistry, Faculty of Science, Charles University in Prague, Prague 2 128 43, Czech Republic
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28
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Sarkar A, Dai Y, Haque MM, Seeger F, Ghosh A, Garcin ED, Montfort WR, Hazen SL, Misra S, Stuehr DJ. Heat Shock Protein 90 Associates with the Per-Arnt-Sim Domain of Heme-free Soluble Guanylate Cyclase: IMplications for Enzyme Maturation. J Biol Chem 2015; 290:21615-28. [PMID: 26134567 DOI: 10.1074/jbc.m115.645515] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Indexed: 11/06/2022] Open
Abstract
Heat shock protein 90 (hsp90) drives heme insertion into the β1 subunit of soluble guanylate cyclase (sGC) β1, which enables it to associate with a partner sGCα1 subunit and mature into a nitric oxide (NO)-responsive active form. We utilized fluorescence polarization measurements and hydrogen-deuterium exchange mass spectrometry to define molecular interactions between the specific human isoforms hsp90β and apo-sGCβ1. hsp90β and its isolated M domain, but not its isolated N and C domains, bind with low micromolar affinity to a heme-free, truncated version of sGCβ1 (sGCβ1(1-359)-H105F). Surprisingly, hsp90β and its M domain bound to the Per-Arnt-Sim (PAS) domain of apo-sGC-β1(1-359), which lies adjacent to its heme-binding (H-NOX) domain. The interaction specifically involved solvent-exposed regions in the hsp90β M domain that are largely distinct from sites utilized by other hsp90 clients. The interaction strongly protected two regions of the sGCβ1 PAS domain and caused local structural relaxation in other regions, including a PAS dimerization interface and a segment in the H-NOX domain. Our results suggest a means by which the hsp90β interaction could prevent apo-sGCβ1 from associating with its partner sGCα1 subunit while enabling structural changes to assist heme insertion into the H-NOX domain. This mechanism would parallel that in other clients like the aryl hydrocarbon receptor and HIF1α, which also interact with hsp90 through their PAS domains to control protein partner and small ligand binding interactions.
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Affiliation(s)
| | - Yue Dai
- From the Departments of Pathobiology
| | | | - Franziska Seeger
- the Department of Chemistry and Biochemistry, University of Maryland at Baltimore County, Baltimore, Maryland 21250, and
| | | | - Elsa D Garcin
- the Department of Chemistry and Biochemistry, University of Maryland at Baltimore County, Baltimore, Maryland 21250, and
| | - William R Montfort
- the Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721
| | | | - Saurav Misra
- Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio 44195
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29
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Wobst J, Rumpf PM, Dang TA, Segura-Puimedon M, Erdmann J, Schunkert H. Molecular variants of soluble guanylyl cyclase affecting cardiovascular risk. Circ J 2015; 79:463-9. [PMID: 25746521 DOI: 10.1253/circj.cj-15-0025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Soluble guanylyl cyclase (sGC) is the physiological receptor for nitric oxide (NO) and NO-releasing drugs, and is a key enzyme in several cardiovascular signaling pathways. Its activation induces the synthesis of the second messenger cGMP. cGMP regulates the activity of various downstream proteins, including cGMP-dependent protein kinase G, cGMP-dependent phosphodiesterases and cyclic nucleotide gated ion channels leading to vascular relaxation, inhibition of platelet aggregation, and modified neurotransmission. Diminished sGC function contributes to a number of disorders, including cardiovascular diseases. Knowledge of its regulation is a prerequisite for understanding the pathophysiology of deficient sGC signaling. In this review we consolidate the available information on sGC signaling, including the molecular biology and genetics of sGC transcription, translation and function, including the effect of rare variants, and present possible new targets for the development of personalized medicine in vascular diseases.
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Affiliation(s)
- Jana Wobst
- Department of Cardiovascular Diseases, German Heart Center Munich, Technical University Munich
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30
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Steegborn C. Structure, mechanism, and regulation of soluble adenylyl cyclases — similarities and differences to transmembrane adenylyl cyclases. Biochim Biophys Acta Mol Basis Dis 2014; 1842:2535-47. [DOI: 10.1016/j.bbadis.2014.08.012] [Citation(s) in RCA: 142] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Revised: 08/19/2014] [Accepted: 08/26/2014] [Indexed: 12/14/2022]
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31
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Structures of soluble guanylate cyclase: implications for regulatory mechanisms and drug development. Biochem Soc Trans 2014; 42:108-13. [PMID: 24450636 PMCID: PMC3901396 DOI: 10.1042/bst20130228] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Activation of cGMP synthesis leads to vasodilation, and is an important mechanism in clinical treatment of angina, heart failure, and severe peripheral and pulmonary hypertension. The nitric oxide-responsive sGC (soluble guanylate cyclase) has been the target of recent drug discovery efforts. The present review surveys recent data on the structure and regulation of sGC, and the prospects of new avenues for therapeutic intervention.
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32
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Heinemann SH, Hoshi T, Westerhausen M, Schiller A. Carbon monoxide--physiology, detection and controlled release. Chem Commun (Camb) 2014; 50:3644-60. [PMID: 24556640 PMCID: PMC4072318 DOI: 10.1039/c3cc49196j] [Citation(s) in RCA: 291] [Impact Index Per Article: 29.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Carbon monoxide (CO) is increasingly recognized as a cell-signalling molecule akin to nitric oxide (NO). CO has attracted particular attention as a potential therapeutic agent because of its reported anti-hypertensive, anti-inflammatory and cell-protective effects. We discuss recent progress in identifying new effector systems and elucidating the mechanisms of action of CO on, e.g., ion channels, as well as the design of novel methods to monitor CO in cellular environments. We also report on recent developments in the area of CO-releasing molecules (CORMs) and materials for controlled CO application. Novel triggers for CO release, metal carbonyls and degradation mechanisms of CORMs are highlighted. In addition, potential formulations of CORMs for targeted CO release are discussed.
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Affiliation(s)
- Stefan H. Heinemann
- Center for Molecular Biomedicine (CMB), Department of Biophysics, Friedrich Schiller University Jena & Jena University Hospital, Hans-Knöll-Straße 2, D-07745 Jena, Germany
| | - Toshinori Hoshi
- Department of Physiology, University of Pennsylvania, 415 Curie Boulevard, 605 CRB, Philadelphia, PA 19104-6085, USA
| | - Matthias Westerhausen
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstr. 8, D-07743 Jena, Germany
| | - Alexander Schiller
- Institute for Inorganic and Analytical Chemistry, Friedrich Schiller University Jena, Humboldtstr. 8, D-07743 Jena, Germany
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33
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Rogers NM, Seeger F, Garcin ED, Roberts DD, Isenberg JS. Regulation of soluble guanylate cyclase by matricellular thrombospondins: implications for blood flow. Front Physiol 2014; 5:134. [PMID: 24772092 PMCID: PMC3983488 DOI: 10.3389/fphys.2014.00134] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 03/18/2014] [Indexed: 01/16/2023] Open
Abstract
Nitric oxide (NO) maintains cardiovascular health by activating soluble guanylate cyclase (sGC) to increase cellular cGMP levels. Cardiovascular disease is characterized by decreased NO-sGC-cGMP signaling. Pharmacological activators and stimulators of sGC are being actively pursued as therapies for acute heart failure and pulmonary hypertension. Here we review molecular mechanisms that modulate sGC activity while emphasizing a novel biochemical pathway in which binding of the matricellular protein thrombospondin-1 (TSP1) to the cell surface receptor CD47 causes inhibition of sGC. We discuss the therapeutic implications of this pathway for blood flow, tissue perfusion, and cell survival under physiologic and disease conditions.
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Affiliation(s)
- Natasha M Rogers
- Department of Medicine, Vascular Medicine Institute, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
| | - Franziska Seeger
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County Baltimore, MD, USA
| | - Elsa D Garcin
- Department of Chemistry and Biochemistry, University of Maryland Baltimore County Baltimore, MD, USA
| | - David D Roberts
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, NIH Bethesda, MD, USA
| | - Jeffrey S Isenberg
- Department of Medicine, Vascular Medicine Institute, University of Pittsburgh School of Medicine Pittsburgh, PA, USA ; Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh School of Medicine Pittsburgh, PA, USA
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Seeger F, Quintyn R, Tanimoto A, Williams GJ, Tainer JA, Wysocki VH, Garcin ED. Interfacial residues promote an optimal alignment of the catalytic center in human soluble guanylate cyclase: heterodimerization is required but not sufficient for activity. Biochemistry 2014; 53:2153-65. [PMID: 24669844 PMCID: PMC3985721 DOI: 10.1021/bi500129k] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
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Soluble guanylate cyclase (sGC) plays
a central role in the cardiovascular
system and is a drug target for the treatment of pulmonary hypertension.
While the three-dimensional structure of sGC is unknown, studies suggest
that binding of the regulatory domain to the catalytic domain maintains
sGC in an autoinhibited basal state. The activation signal, binding
of NO to heme, is thought to be transmitted via the regulatory and
dimerization domains to the cyclase domain and unleashes the full
catalytic potential of sGC. Consequently, isolated catalytic domains
should show catalytic turnover comparable to that of activated sGC.
Using X-ray crystallography, activity measurements, and native mass
spectrometry, we show unambiguously that human isolated catalytic
domains are much less active than basal sGC, while still forming heterodimers.
We identified key structural elements regulating the dimer interface
and propose a novel role for residues located in an interfacial flap
and a hydrogen bond network as key modulators of the orientation of
the catalytic subunits. We demonstrate that even in the absence of
the regulatory domain, additional sGC domains are required to guide
the appropriate conformation of the catalytic subunits associated
with high activity. Our data support a novel regulatory mechanism
whereby sGC activity is tuned by distinct domain interactions that
either promote or inhibit catalytic activity. These results further
our understanding of heterodimerization and activation of sGC and
open additional drug discovery routes for targeting the NO–sGC–cGMP
pathway via the design of small molecules that promote a productive
conformation of the catalytic subunits or disrupt inhibitory domain
interactions.
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Affiliation(s)
- Franziska Seeger
- University of Maryland Baltimore County , Baltimore, Maryland 21250, United States
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Underbakke ES, Iavarone AT, Chalmers MJ, Pascal BD, Novick S, Griffin PR, Marletta MA. Nitric oxide-induced conformational changes in soluble guanylate cyclase. Structure 2014; 22:602-11. [PMID: 24560804 DOI: 10.1016/j.str.2014.01.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/07/2014] [Accepted: 01/13/2014] [Indexed: 01/24/2023]
Abstract
Soluble guanylate cyclase (sGC) is the primary mediator of nitric oxide (NO) signaling. NO binds the sGC heme cofactor stimulating synthesis of the second messenger cyclic-GMP (cGMP). As the central hub of NO/cGMP signaling pathways, sGC is important in diverse physiological processes such as vasodilation and neurotransmission. Nevertheless, the mechanisms underlying NO-induced cyclase activation in sGC remain unclear. Here, hydrogen/deuterium exchange mass spectrometry (HDX-MS) was employed to probe the NO-induced conformational changes of sGC. HDX-MS revealed NO-induced effects in several discrete regions. NO binding to the heme-NO/O2-binding (H-NOX) domain perturbs a signaling surface implicated in Per/Arnt/Sim (PAS) domain interactions. Furthermore, NO elicits striking conformational changes in the junction between the PAS and helical domains that propagate as perturbations throughout the adjoining helices. Ultimately, NO binding stimulates the catalytic domain by contracting the active site pocket. Together, these conformational changes delineate an allosteric pathway linking NO binding to activation of the catalytic domain.
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Affiliation(s)
- Eric S Underbakke
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Anthony T Iavarone
- Department of Chemistry and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael J Chalmers
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Bruce D Pascal
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Scott Novick
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Patrick R Griffin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Michael A Marletta
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, USA.
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Single-particle EM reveals the higher-order domain architecture of soluble guanylate cyclase. Proc Natl Acad Sci U S A 2014; 111:2960-5. [PMID: 24516165 DOI: 10.1073/pnas.1400711111] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Soluble guanylate cyclase (sGC) is the primary nitric oxide (NO) receptor in mammals and a central component of the NO-signaling pathway. The NO-signaling pathways mediate diverse physiological processes, including vasodilation, neurotransmission, and myocardial functions. sGC is a heterodimer assembled from two homologous subunits, each comprised of four domains. Although crystal structures of isolated domains have been reported, no structure is available for full-length sGC. We used single-particle electron microscopy to obtain the structure of the complete sGC heterodimer and determine its higher-order domain architecture. Overall, the protein is formed of two rigid modules: the catalytic dimer and the clustered Per/Art/Sim and heme-NO/O2-binding domains, connected by a parallel coiled coil at two hinge points. The quaternary assembly demonstrates a very high degree of flexibility. We captured hundreds of individual conformational snapshots of free sGC, NO-bound sGC, and guanosine-5'-[(α,β)-methylene]triphosphate-bound sGC. The molecular architecture and pronounced flexibility observed provides a significant step forward in understanding the mechanism of NO signaling.
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37
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Purohit R, Fritz BG, The J, Issaian A, Weichsel A, David CL, Campbell E, Hausrath AC, Rassouli-Taylor L, Garcin ED, Gage MJ, Montfort WR. YC-1 binding to the β subunit of soluble guanylyl cyclase overcomes allosteric inhibition by the α subunit. Biochemistry 2013; 53:101-14. [PMID: 24328155 DOI: 10.1021/bi4015133] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Soluble guanylate cyclase (sGC) is a heterodimeric heme protein and the primary nitric oxide receptor. NO binding stimulates cyclase activity, leading to regulation of cardiovascular physiology and making sGC an attractive target for drug discovery. YC-1 and related compounds stimulate sGC both independently and synergistically with NO and CO binding; however, where the compounds bind and how they work remain unknown. Using linked equilibrium binding measurements, surface plasmon resonance, and domain truncations in Manduca sexta and bovine sGC, we demonstrate that YC-1 binds near or directly to the heme-containing domain of the β subunit. In the absence of CO, YC-1 binds with a Kd of 9-21 μM, depending on the construct. In the presence of CO, these values decrease to 0.6-1.1 μM. Pfizer compound 25 bound ∼10-fold weaker than YC-1 in the absence of CO, whereas compound BAY 41-2272 bound particularly tightly in the presence of CO (Kd = 30-90 nM). Additionally, we found that CO binds much more weakly to heterodimeric sGC proteins (Kd = 50-100 μM) than to the isolated heme domain (Kd = 0.2 μM for Manduca β H-NOX/PAS). YC-1 greatly enhanced binding of CO to heterodimeric sGC, as expected (Kd ∼ 1 μM). These data indicate the α subunit induces a heme pocket conformation with a lower affinity for CO and NO. YC-1 family compounds bind near the heme domain, overcoming the α subunit effect and inducing a heme pocket conformation with high affinity. We propose this high-affinity conformation is required for the full-length protein to achieve high catalytic activity.
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Affiliation(s)
- Rahul Purohit
- Department of Chemistry and Biochemistry, The University of Arizona , Tucson, Arizona 85721, United States
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Busker M, Neidhardt I, Behrends S. Nitric oxide activation of guanylate cyclase pushes the α1 signaling helix and the β1 heme-binding domain closer to the substrate-binding site. J Biol Chem 2013; 289:476-84. [PMID: 24220034 DOI: 10.1074/jbc.m113.504472] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The complete structure of the assembled domains of nitric oxide-sensitive guanylate cyclase (NOsGC) remains to be determined. It is also unknown how binding of NO to heme in guanylate cyclase is communicated to the catalytic domain. In the current study the conformational change of guanylate cyclase on activation by NO was studied using FRET. Endogenous tryptophan residues were used as donors, the substrate analog 2'-Mant-3'-dGTP as acceptor. The enzyme contains five tryptophan residues distributed evenly over all four functional domains. This provides a unique opportunity to detect the movement of the functional domains relative to the substrate-binding catalytic region. FRET measurements indicate that NO brings tryptophan 22 in the αB helix of the β1 heme NO binding domain and tryptophan 466 in the second short helix of the α1 coiled-coil domain closer to the catalytic domain. We propose that the respective domains act as a pair of tongs forcing the catalytic domain into the nitric oxide-activated conformation.
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Affiliation(s)
- Mareike Busker
- From the Department of Pharmacology, Toxicology and Clinical Pharmacy, University of Braunschweig-Institute of Technology, D-38106 Braunschweig, Germany
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