1
|
Hillebrand L, Liang XJ, Serafim RAM, Gehringer M. Emerging and Re-emerging Warheads for Targeted Covalent Inhibitors: An Update. J Med Chem 2024; 67:7668-7758. [PMID: 38711345 DOI: 10.1021/acs.jmedchem.3c01825] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Covalent inhibitors and other types of covalent modalities have seen a revival in the past two decades, with a variety of new targeted covalent drugs having been approved in recent years. A key feature of such molecules is an intrinsically reactive group, typically a weak electrophile, which enables the irreversible or reversible formation of a covalent bond with a specific amino acid of the target protein. This reactive group, often called the "warhead", is a critical determinant of the ligand's activity, selectivity, and general biological properties. In 2019, we summarized emerging and re-emerging warhead chemistries to target cysteine and other amino acids (Gehringer, M.; Laufer, S. A. J. Med. Chem. 2019, 62, 5673-5724; DOI: 10.1021/acs.jmedchem.8b01153). Since then, the field has rapidly evolved. Here we discuss the progress on covalent warheads made since our last Perspective and their application in medicinal chemistry and chemical biology.
Collapse
Affiliation(s)
- Laura Hillebrand
- Department of Pharmaceutical/Medicinal Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Xiaojun Julia Liang
- Department of Pharmaceutical/Medicinal Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided & Functionally Instructed Tumor Therapies", University of Tübingen, 72076 Tübingen, Germany
| | - Ricardo A M Serafim
- Department of Pharmaceutical/Medicinal Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
| | - Matthias Gehringer
- Department of Pharmaceutical/Medicinal Chemistry, Eberhard Karls University Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided & Functionally Instructed Tumor Therapies", University of Tübingen, 72076 Tübingen, Germany
| |
Collapse
|
2
|
Mahmood Janlou MA, Sahebjamee H, Yazdani M, Fozouni L. Structure-based virtual screening and molecular dynamics approaches to identify new inhibitors of Staphylococcus aureus sortase A. J Biomol Struct Dyn 2024; 42:1157-1169. [PMID: 37184111 DOI: 10.1080/07391102.2023.2201863] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Accepted: 03/28/2023] [Indexed: 05/16/2023]
Abstract
Staphylococcus aureus is a prevalent Gram-positive bacteria leading cause of a wide range of human pathologies. Moreover, antibiotic résistance of pathogenesis bacteria is one of the worldwide health problems. In Gram-positive bacteria, the enzyme of SrtA, is responsible for the anchoring of surface-exposed proteins to the cell wall peptidoglycan. Because of its critical role in Gram-positive bacterial pathogenesis, SrtA is an attractive target for anti-virulence during drug development. To date, some SrtA inhibitors have been discovered most of them being derived from flavonoid compounds, like Myricetin. In order to provide potential hit molecules against SrtA for clinical use, we obtained a total of 293 compounds by performing in silico shape-based screening of compound libraries against Myristin as a reference structure. Employing molecular docking and scoring functions, the top 3 compounds Apigenin, Efloxate, and Compound 8261032 were screened by comparing their docking scores with Myricetin. Furthermore, MD simulations and MM-PBSA binding energy calculation studies revealed that only Compound 8261032 strongly binds to the catalytic core of the SrtA enzyme than Myricetin, and stable behavior was consistently observed in the docking complex. Compound 8261032 showed a good number of hydrogen bonds with SrtA and higher MM-PBSA binding energy when compared to all three molecules. Also, it makes strength interactions with Arg139 and His62, which are critical for SrtA biological activity. This study showed that the development of this inhibitor could be a fundamental strategy against resistant bacteria, but further studies in vitro are needed to confirm this claim.Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Mehr Ali Mahmood Janlou
- Department of Biophysics, Faculty of Biological Sciences, Gorgan Branch, Islamic Azad University, Gorgan, Iran
| | - Hassan Sahebjamee
- Department of Biophysics, Faculty of Biological Science, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran
| | - Mohsen Yazdani
- Laboratory of Bioinformatics and Drug Design, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Leila Fozouni
- Department of Microbiology, Faculty of Biological Sciences, Gorgan Branch, Islamic Azad University, Gorgan, Iran
| |
Collapse
|
3
|
Liu K, Tong J, Liu X, Liang D, Ren F, Jiang N, Hao Z, Li S, Wang Q. The Discovery of Novel Agents against Staphylococcus aureus by Targeting Sortase A: A Combination of Virtual Screening and Experimental Validation. Pharmaceuticals (Basel) 2023; 17:58. [PMID: 38256891 PMCID: PMC11100315 DOI: 10.3390/ph17010058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/12/2023] [Accepted: 12/16/2023] [Indexed: 01/24/2024] Open
Abstract
Staphylococcus aureus (S. aureus), commonly known as "superbugs", is a highly pathogenic bacterium that poses a serious threat to human health. There is an urgent need to replace traditional antibiotics with novel drugs to combat S. aureus. Sortase A (SrtA) is a crucial transpeptidase involved in the adhesion process of S. aureus. The reduction in virulence and prevention of S. aureus infections have made it a significant target for antimicrobial drugs. In this study, we combined virtual screening with experimental validation to identify potential drug candidates from a drug library. Three hits, referred to as Naldemedine, Telmisartan, and Azilsartan, were identified based on docking binding energy and the ratio of occupied functional sites of SrtA. The stability analysis manifests that Naldemedine and Telmisartan have a higher binding affinity to the hydrophobic pockets. Specifically, Telmisartan forms stable hydrogen bonds with SrtA, resulting in the highest binding energy. Our experiments prove that the efficiency of adhesion and invasion by S. aureus can be decreased without significantly affecting bacterial growth. Our work identifies Telmisartan as the most promising candidate for inhibiting SrtA, which can help combat S. aureus infection.
Collapse
Affiliation(s)
- Kang Liu
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Jiangbo Tong
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Xu Liu
- College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225009, China;
| | - Dan Liang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Fangzhe Ren
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Nan Jiang
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Zhenyu Hao
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Shixin Li
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China; (K.L.); (J.T.); (D.L.); (F.R.); (N.J.); (Z.H.)
| | - Qiang Wang
- Department of the Heart and Great Vessels, Affiliated Hospital of Yangzhou University, Yangzhou 225009, China
| |
Collapse
|
4
|
Mangal P, Jha RK, Jain M, Singh AK, Muthukumaran J. Identification and prioritization of promising lead molecules from Syzygium aromaticum against Sortase C from Streptococcus pyogenes: an in silico investigation. J Biomol Struct Dyn 2022:1-18. [PMID: 35706070 DOI: 10.1080/07391102.2022.2086921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Sortases are extracellular transpeptidases that play an essential role in the adhesion of secreted proteins to the peptidoglycan layer of the cell wall of Gram-negative bacteria. Sortases are an important drug target protein due to their involvement in synthesizing the peptidoglycan cell wall of Streptococcus pyogenes, and these are not found in Homo sapiens. In this study, initially, we have performed protein sequence analysis to understand the sequential properties of Sortase C. Next, a comparative protein modeling approach was used to predict the three-dimensional model of Sortase C based on the crystal structure of Sortase C from Streptococcus pneumoniae. Virtual screening with an in-house library of phytochemicals from Syzygium aromaticum and molecular docking studies were performed to identify the promising lead molecules. These compounds were also analyzed for their drug-like and pharmacokinetic properties. Subsequently, the protein-ligand complexes of the selected ligands were subjected to molecular dynamics (MD) simulations to investigate their dynamic behavior in physiological conditions. The global and essential dynamics analyses result implied that the Sortase C complexes of the proposed three lead candidates exhibited adequate stability during the MD simulations. Additionally, the three proposed molecules showed favorable MM/PBSA binding free energy values ranging from -13.8 +/- 9.41 to -56.6 +/- 8.82 kcal/mol. After an extensive computational investigation, we have identified three promising lead candidates (CID:13888122, CID:3694932 and CID:102445430) against Sortase C from S. pyogenes. The result obtained from these computational studies can be used to screen and develop the inhibitors against Sortase C from S. pyogenes. Communicated by Ramaswamy H. Sarma.
Collapse
Affiliation(s)
- Purti Mangal
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| | - Rajat Kumar Jha
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| | - Monika Jain
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| | - Amit Kumar Singh
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| | - Jayaraman Muthukumaran
- Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, India
| |
Collapse
|
5
|
Guan XN, Zhang T, Yang T, Dong Z, Yang S, Lan L, Gan J, Yang CG. Covalent sortase A inhibitor ML346 prevents Staphylococcus aureus infection of Galleria mellonella. RSC Med Chem 2022; 13:138-149. [PMID: 35308030 PMCID: PMC8864484 DOI: 10.1039/d1md00316j] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/31/2021] [Indexed: 12/16/2023] Open
Abstract
The housekeeping sortase A (SrtA), a membrane-associated cysteine transpeptidase, is responsible for anchoring surface proteins to the cell wall peptidoglycan in Gram-positive bacteria. This process is essential for the regulation of bacterial virulence and pathogenicity. Therefore, SrtA is considered to be an ideal target for antivirulence therapy. In this study, we report that ML346, a compound with a barbituric acid and cinnamaldehyde scaffold, functions as an irreversible inhibitor of Staphylococcus aureus SrtA (SaSrtA) and Streptococcus pyogenes SrtA (SpSrtA) in vitro at low micromolar concentrations. According to our X-ray crystal structure of the SpSrtAΔN81/ML346 complex (Protein Data Bank ID: 7V6K), ML346 covalently modifies the thiol group of Cys208 in the active site of SpSrtA. Importantly, ML346 significantly attenuated the virulence phenotypes of S. aureus and exhibited inhibitory effects on Galleria mellonella larva infection caused by S. aureus. Collectively, our results indicate that ML346 has potential for development as a covalent antivirulence agent for treating S. aureus infections, including methicillin-resistant S. aureus.
Collapse
Affiliation(s)
- Xiang-Na Guan
- Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- University of the Chinese Academy of Sciences Beijing 100049 China
| | - Tao Zhang
- Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
| | - Teng Yang
- Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University Guiyang 550025 China
| | - Ze Dong
- Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
| | - Song Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University Guiyang 550025 China
| | - Lefu Lan
- Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- University of the Chinese Academy of Sciences Beijing 100049 China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences Hangzhou 310024 China
| | - Jianhua Gan
- School of Life Sciences, Fudan University Shanghai 200433 China
| | - Cai-Guang Yang
- Center for Chemical Biology, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences Shanghai 201203 China
- University of the Chinese Academy of Sciences Beijing 100049 China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences Hangzhou 310024 China
| |
Collapse
|
6
|
Barthels F, Meyr J, Hammerschmidt SJ, Marciniak T, Räder HJ, Ziebuhr W, Engels B, Schirmeister T. 2-Sulfonylpyrimidines as Privileged Warheads for the Development of S. aureus Sortase A Inhibitors. Front Mol Biosci 2022; 8:804970. [PMID: 35047562 PMCID: PMC8763382 DOI: 10.3389/fmolb.2021.804970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/03/2021] [Indexed: 11/29/2022] Open
Abstract
Staphylococcus aureus is one of the most frequent causes of nosocomial and community-acquired infections, with emerging multiresistant isolates causing a significant burden to public health systems. We identified 2-sulfonylpyrimidines as a new class of potent inhibitors against S. aureus sortase A acting by covalent modification of the active site cysteine 184. Series of derivatives were synthesized to derive structure-activity relationship (SAR) with the most potent compounds displaying low micromolar KI values. Studies on the inhibition selectivity of homologous cysteine proteases showed that 2-sulfonylpyrimidines reacted efficiently with protonated cysteine residues as found in sortase A, though surprisingly, no reaction occurred with the more nucleophilic cysteine residue from imidazolinium-thiolate dyads of cathepsin-like proteases. By means of enzymatic and chemical kinetics as well as quantum chemical calculations, it could be rationalized that the SNAr reaction between protonated cysteine residues and 2-sulfonylpyrimidines proceeds in a concerted fashion, and the mechanism involves a ternary transition state with a conjugated base. Molecular docking and enzyme inhibition at variable pH values allowed us to hypothesize that in sortase A this base is represented by the catalytic histidine 120, which could be substantiated by QM model calculation with 4-methylimidazole as histidine analog.
Collapse
Affiliation(s)
- Fabian Barthels
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Mainz, Germany
| | - Jessica Meyr
- Institute of Physical and Theoretical Chemistry, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - Stefan J Hammerschmidt
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Mainz, Germany
| | - Tessa Marciniak
- Institute for Molecular Infection Biology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | | | - Wilma Ziebuhr
- Institute for Molecular Infection Biology, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - Bernd Engels
- Institute of Physical and Theoretical Chemistry, Julius-Maximilians-University of Würzburg, Würzburg, Germany
| | - Tanja Schirmeister
- Institute for Pharmaceutical and Biomedical Sciences, Johannes Gutenberg-University, Mainz, Germany
| |
Collapse
|
7
|
Sapra R, Rajora AK, Kumar P, Maurya GP, Pant N, Haridas V. Chemical Biology of Sortase A Inhibition: A Gateway to Anti-infective Therapeutic Agents. J Med Chem 2021; 64:13097-13130. [PMID: 34516107 DOI: 10.1021/acs.jmedchem.1c00386] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Staphylococcus aureus is the leading cause of hospital-acquired infections. The enzyme sortase A, present on the cell surface of S. aureus, plays a key role in bacterial virulence without affecting the bacterial viability. Inhibition of sortase A activity offers a powerful but clinically less explored therapeutic strategy, as it offers the possibility of not inducing any selective pressure on the bacteria to evolve drug-resistant strains. In this Perspective, we offer a chemical space narrative for the design of sortase A inhibitors, as delineated into three broad domains: peptidomimetics, natural products, and synthetic small molecules. This provides immense opportunities for medicinal chemists to alleviate the ever-growing crisis of antibiotic resistance.
Collapse
Affiliation(s)
- Rachit Sapra
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi-110016, India
| | - Amit K Rajora
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi-110016, India
| | - Pushpendra Kumar
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi-110016, India
| | - Govind P Maurya
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi-110016, India
| | - Nalin Pant
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi-110016, India
| | - V Haridas
- Department of Chemistry, Indian Institute of Technology Delhi, New Delhi-110016, India
| |
Collapse
|
8
|
Wang L, Wang G, Qu H, Wang K, Jing S, Guan S, Su L, Li Q, Wang D. Taxifolin, an Inhibitor of Sortase A, Interferes With the Adhesion of Methicillin-Resistant Staphylococcal aureus. Front Microbiol 2021; 12:686864. [PMID: 34295320 PMCID: PMC8290497 DOI: 10.3389/fmicb.2021.686864] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Accepted: 06/14/2021] [Indexed: 11/30/2022] Open
Abstract
The evolution and spread of methicillin-resistant Staphylococcus aureus (MRSA) poses a significant hidden risk to human public health. The majority of antibiotics used clinically have become mostly ineffective, and so the development of novel anti-infection strategies is urgently required. Since Staphylococcus aureus (S. aureus) cysteine transpeptidase sortase A (SrtA) mediates the surface-anchoring of proteins to its surface, compounds that inhibit SrtA are considered potential antivirulence treatments. Herein, we report on the efficacy of the potent SrtA inhibitor taxifolin (Tax), a flavonoid compound isolated from Chinese herbs. It was able to reversibly block the activity of SrtA with an IC50 of 24.53 ± 0.42 μM. Tax did not display toxicity toward mammalian cells or S. aureus at a concentration of 200 μM. In addition, Tax attenuated the virulence-related phenotype of SrtA in vitro by decreasing the adherence of S. aureus, reducing the formation of a biofilm, and anchoring of S. aureus protein A on its cell wall. The mechanism of the SrtA-Tax interaction was determined using a localized surface plasmon resonance assay. Subsequent mechanistic studies confirmed that Asp-170 and Gln-172 were the principal sites on SrtA with which it binds to Tax. Importantly, in vivo experiments demonstrated that Tax protects mice against pneumonia induced by lethal doses of MRSA, significantly improving their survival rate and reducing the number of viable S. aureus in the lung tissue. The present study indicates that Tax is a useful pioneer compound for the development of novel agents against S. aureus infections.
Collapse
Affiliation(s)
- Li Wang
- College of Animal Science, Jilin University, Changchun, China
| | - Guangming Wang
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | - Han Qu
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Kai Wang
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Shisong Jing
- College of Animal Science, Jilin University, Changchun, China
| | - Shuhan Guan
- College of Animal Science, Jilin University, Changchun, China
| | - Liyan Su
- College of Veterinary Medicine, Jilin University, Changchun, China
| | - Qianxue Li
- Changchun Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Dacheng Wang
- College of Animal Science, Jilin University, Changchun, China
| |
Collapse
|
9
|
Nitulescu G, Margina D, Zanfirescu A, Olaru OT, Nitulescu GM. Targeting Bacterial Sortases in Search of Anti-Virulence Therapies with Low Risk of Resistance Development. Pharmaceuticals (Basel) 2021; 14:ph14050415. [PMID: 33946434 PMCID: PMC8147154 DOI: 10.3390/ph14050415] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 12/29/2022] Open
Abstract
Increasingly ineffective antibiotics and rapid spread of multi- and pan-resistant bacteria represent a global health threat; hence, the need of developing new antimicrobial medicines. A first step in this direction is identifying new molecular targets, such as virulence factors. Sortase A represents a virulence factor essential for the pathogenesis of Gram-positive pathogens, some of which have a high risk for human health. We present here an exhaustive collection of sortases inhibitors grouped by relevant chemical features: vinyl sulfones, 3-aryl acrylic acids and derivatives, flavonoids, naphtoquinones, anthraquinones, indoles, pyrrolomycins, isoquinoline derivatives, aryl β-aminoethyl ketones, pyrazolethiones, pyridazinones, benzisothiazolinones, 2-phenyl-benzoxazole and 2-phenyl-benzofuran derivatives, thiadiazoles, triazolothiadiazoles, 2-(2-phenylhydrazinylidene)alkanoic acids, and 1,2,4-thiadiazolidine-3,5-dione. This review focuses on highlighting their structure–activity relationships, using the half maximal inhibitory concentration (IC50), when available, as an indicator of each compound effect on a specific sortase. The information herein is useful for acquiring knowledge on diverse natural and synthetic sortases inhibitors scaffolds and for understanding the way their structural variations impact IC50. It will hopefully be the inspiration for designing novel effective and safe sortase inhibitors in order to create new anti-infective compounds and to help overcoming the current worldwide antibiotic shortage.
Collapse
|
10
|
Alharthi S, Alavi SE, Moyle PM, Ziora ZM. Sortase A (SrtA) inhibitors as an alternative treatment for superbug infections. Drug Discov Today 2021; 26:2164-2172. [PMID: 33781954 DOI: 10.1016/j.drudis.2021.03.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/01/2021] [Accepted: 03/19/2021] [Indexed: 12/28/2022]
Abstract
Virulence factor, sortase A (SrtA), has crucial roles in the pathogenesis of Gram-positive superbugs. SrtA is a bacterial cell membrane enzyme that anchors crucial virulence factors to the cell wall surface of Gram-positive bacteria. SrtA is not necessary for bacterial growth and viability and is conveniently accessible in the cell membrane; therefore, it is an ideal target for antivirulence drug development. In this review, we focus on antimicrobial resistance (AMR)-expressing bacteria and SrtA as a potential target for overcoming AMR. The mechanism of action of SrtA and its inhibition by various types of inhibitors, such as synthetic small molecules, peptides, and natural products, are provided. Future SrtA research perspectives for alternative drug development to antibiotics are also proposed.
Collapse
Affiliation(s)
- Sitah Alharthi
- School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia; Department of Pharmaceutical Science, School of Pharmacy, Shaqra University, Riyadh, Saudi Arabia
| | - Seyed Ebrahim Alavi
- School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia
| | - Peter Michael Moyle
- School of Pharmacy, The University of Queensland, Woolloongabba, Qld 4102, Australia.
| | - Zyta Maria Ziora
- Institute for Molecular Bioscience, The University of Queensland, St Lucia, Qld 4067, Australia.
| |
Collapse
|
11
|
Zrelovs N, Kurbatska V, Rudevica Z, Leonchiks A, Fridmanis D. Sorting out the Superbugs: Potential of Sortase A Inhibitors among Other Antimicrobial Strategies to Tackle the Problem of Antibiotic Resistance. Antibiotics (Basel) 2021; 10:164. [PMID: 33562778 PMCID: PMC7916047 DOI: 10.3390/antibiotics10020164] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/31/2021] [Accepted: 02/02/2021] [Indexed: 12/22/2022] Open
Abstract
Rapid spread of antibiotic resistance throughout the kingdom bacteria is inevitably bringing humanity towards the "post-antibiotic" era. The emergence of so-called "superbugs"-pathogen strains that develop resistance to multiple conventional antibiotics-is urging researchers around the globe to work on the development or perfecting of alternative means of tackling the pathogenic bacteria infections. Although various conceptually different approaches are being considered, each comes with its advantages and drawbacks. While drug-resistant pathogens are undoubtedly represented by both Gram(+) and Gram(-) bacteria, possible target spectrum across the proposed alternative approaches of tackling them is variable. Numerous anti-virulence strategies aimed at reducing the pathogenicity of target bacteria rather than eliminating them are being considered among such alternative approaches. Sortase A (SrtA) is a membrane-associated cysteine protease that catalyzes a cell wall sorting reaction by which surface proteins, including virulence factors, are anchored to the bacterial cell wall of Gram(+) bacteria. Although SrtA inhibition seems perspective among the Gram-positive pathogen-targeted antivirulence strategies, it still remains less popular than other alternatives. A decrease in virulence due to inactivation of SrtA activity has been extensively studied in Staphylococcus aureus, but it has also been demonstrated in other Gram(+) species. In this manuscript, results of past studies on the discovery of novel SrtA inhibitory compounds and evaluation of their potency were summarized and commented on. Here, we discussed the rationale behind the inhibition of SrtA, raised some concerns on the comparability of the results from different studies, and touched upon the possible resistance mechanisms as a response to implementation of such therapy in practice. The goal of this article is to encourage further studies of SrtA inhibitory compounds.
Collapse
Affiliation(s)
| | | | | | | | - Davids Fridmanis
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k1, LV-1067 Riga, Latvia; (N.Z.); (V.K.); (Z.R.); (A.L.)
| |
Collapse
|
12
|
Design and Synthesis of Small Molecules as Potent Staphylococcus aureus Sortase A Inhibitors. Antibiotics (Basel) 2020; 9:antibiotics9100706. [PMID: 33081148 PMCID: PMC7602840 DOI: 10.3390/antibiotics9100706] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/11/2020] [Accepted: 10/13/2020] [Indexed: 01/25/2023] Open
Abstract
The widespread and uncontrollable emergence of antibiotic-resistant bacteria, especially methicillin-resistant Staphylococcus aureus, has promoted a wave of efforts to discover a new generation of antibiotics that prevent or treat bacterial infections neither as bactericides nor bacteriostats. Due to its crucial role in virulence and its nonessentiality in bacterial survival, sortase A has been considered as a great target for new antibiotics. Sortase A inhibitors have emerged as promising alternative antivirulence agents against bacteria. Herein, the structural and preparative aspects of some small synthetic organic compounds that block the pathogenic action of sortase A have been described.
Collapse
|
13
|
Yang T, Zhang T, Guan XN, Dong Z, Lan L, Yang S, Yang CG. Tideglusib and Its Analogues As Inhibitors of Staphylococcus aureus SrtA. J Med Chem 2020; 63:8442-8457. [PMID: 32639734 DOI: 10.1021/acs.jmedchem.0c00803] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sortase A (SrtA) anchors surface proteins to the cell wall envelope, and it has attracted increasing interesting as a potential antivirulence target. Several small-molecule inhibitors for SrtA have been developed, but target validation remains largely underexplored. Herein, we report a new class of SrtA inhibitors that supports antivirulence therapy through small-molecule targeting of SrtA. Tideglusib (TD), a drug candidate for myotonic dystrophy, was outstanding in high-throughput screening. A concise synthetic route quickly provided TD analogues, and the structure-activity relationships for SrtA inhibition have been established from those analogues. Several compounds largely retained the in vitro potency and exhibited a better solubility than TD. Additionally, TD attenuated virulence-related phenotypes in vitro and protected mice against lethal S. aureus USA300 bacteremia. Our study indicates that TD and its analogues could be new candidates as SrtA inhibitors with potential in the development of new antivirulence agents.
Collapse
Affiliation(s)
- Teng Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, Guizhou 550025, China.,State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Tao Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Xiang-Na Guan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.,University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Ze Dong
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Lefu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.,University of the Chinese Academy of Sciences, Beijing 100049, China.,School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| | - Song Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, Guizhou 550025, China
| | - Cai-Guang Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China.,University of the Chinese Academy of Sciences, Beijing 100049, China.,School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, UCAS, Hangzhou 310024, China
| |
Collapse
|
14
|
Barthels F, Marincola G, Marciniak T, Konhäuser M, Hammerschmidt S, Bierlmeier J, Distler U, Wich PR, Tenzer S, Schwarzer D, Ziebuhr W, Schirmeister T. Asymmetric Disulfanylbenzamides as Irreversible and Selective Inhibitors of Staphylococcus aureus Sortase A. ChemMedChem 2020; 15:839-850. [PMID: 32118357 PMCID: PMC7318353 DOI: 10.1002/cmdc.201900687] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 02/07/2020] [Indexed: 12/19/2022]
Abstract
Staphylococcus aureus is one of the most frequent causes of nosocomial and community-acquired infections, with drug-resistant strains being responsible for tens of thousands of deaths per year. S. aureus sortase A inhibitors are designed to interfere with virulence determinants. We have identified disulfanylbenzamides as a new class of potent inhibitors against sortase A that act by covalent modification of the active-site cysteine. A broad series of derivatives were synthesized to derive structure-activity relationships (SAR). In vitro and in silico methods allowed the experimentally observed binding affinities and selectivities to be rationalized. The most active compounds were found to have single-digit micromolar Ki values and caused up to a 66 % reduction of S. aureus fibrinogen attachment at an effective inhibitor concentration of 10 μM. This new molecule class exhibited minimal cytotoxicity, low bacterial growth inhibition and impaired sortase-mediated adherence of S. aureus cells.
Collapse
Affiliation(s)
- Fabian Barthels
- Institute for Pharmacy and BiochemistryJohannes-Gutenberg-University of MainzStaudinger Weg 555128MainzGermany
| | - Gabriella Marincola
- Institute for Molecular Infection BiologyJulius-Maximilians-University of WürzburgJosef-Schneider-Strasse 297080WürzburgGermany
| | - Tessa Marciniak
- Institute for Molecular Infection BiologyJulius-Maximilians-University of WürzburgJosef-Schneider-Strasse 297080WürzburgGermany
| | - Matthias Konhäuser
- Institute for Pharmacy and BiochemistryJohannes-Gutenberg-University of MainzStaudinger Weg 555128MainzGermany
| | - Stefan Hammerschmidt
- Institute for Pharmacy and BiochemistryJohannes-Gutenberg-University of MainzStaudinger Weg 555128MainzGermany
| | - Jan Bierlmeier
- Interfaculty Institute of BiochemistryEberhard-Karls-University of TübingenHoppe-Seyler-Strasse 472076TübingenGermany
| | - Ute Distler
- Institute for ImmunologyUniversity Medical CenterJohannes-Gutenberg-University of MainzLangenbeckstr. 155131MainzGermany
- Focus Program Translational Neuroscience (FTN)University Medical CenterLangenbeckstr. 155131MainzGermany
| | - Peter R. Wich
- Institute for Pharmacy and BiochemistryJohannes-Gutenberg-University of MainzStaudinger Weg 555128MainzGermany
- School of Chemical EngineeringUniversity of New South WalesScience and Engineering BuildingSydneyNSW 2052Australia
| | - Stefan Tenzer
- Institute for ImmunologyUniversity Medical CenterJohannes-Gutenberg-University of MainzLangenbeckstr. 155131MainzGermany
| | - Dirk Schwarzer
- Interfaculty Institute of BiochemistryEberhard-Karls-University of TübingenHoppe-Seyler-Strasse 472076TübingenGermany
| | - Wilma Ziebuhr
- Institute for Molecular Infection BiologyJulius-Maximilians-University of WürzburgJosef-Schneider-Strasse 297080WürzburgGermany
| | - Tanja Schirmeister
- Institute for Pharmacy and BiochemistryJohannes-Gutenberg-University of MainzStaudinger Weg 555128MainzGermany
| |
Collapse
|
15
|
Jaudzems K, Kurbatska V, Je̅kabsons A, Bobrovs R, Rudevica Z, Leonchiks A. Targeting Bacterial Sortase A with Covalent Inhibitors: 27 New Starting Points for Structure-Based Hit-to-Lead Optimization. ACS Infect Dis 2020; 6:186-194. [PMID: 31724850 DOI: 10.1021/acsinfecdis.9b00265] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Because of its essential role as a bacterial virulence factor, enzyme sortase A (SrtA) has become an attractive target for the development of new antivirulence drugs against Gram-positive infections. Here we describe 27 compounds identified as covalent inhibitors of Staphylococcus aureus SrtA by screening a library of approximately 50 000 compounds using a FRET assay followed by NMR-based validation and binding reversibility analysis. Nineteen of these compounds displayed only moderate to weak cytotoxicity, with CC50 against NIH 3T3 mice fibroblast cells ranging from 12 to 740 μM. Analysis using covalent docking suggests that the inhibitors initially associate via hydrophobic interactions, followed by covalent bond formation between the SrtA active site cysteine and an electrophilic center of the inhibitor. The compounds represent good starting points that have the potential to be developed into broad spectrum antivirulence agents as exemplified by hit-to-lead optimization of one of the compounds.
Collapse
Affiliation(s)
- Kristaps Jaudzems
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
- Department of Organic Chemistry, University of Latvia, Jelgavas 1, Riga LV-1004, Latvia
| | - Viktorija Kurbatska
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k1, Riga LV-1067, Latvia
| | - Atis Je̅kabsons
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Raitis Bobrovs
- Latvian Institute of Organic Synthesis, Aizkraukles 21, Riga LV-1006, Latvia
| | - Zhanna Rudevica
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k1, Riga LV-1067, Latvia
| | - Ainars Leonchiks
- Latvian Biomedical Research and Study Centre, Ratsupites 1 k1, Riga LV-1067, Latvia
| |
Collapse
|
16
|
Hou X, Wang M, Wen Y, Ni T, Guan X, Lan L, Zhang N, Zhang A, Yang CG. Quinone skeleton as a new class of irreversible inhibitors against Staphylococcus aureus sortase A. Bioorg Med Chem Lett 2018; 28:1864-1869. [PMID: 29650293 DOI: 10.1016/j.bmcl.2018.04.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/30/2018] [Accepted: 04/03/2018] [Indexed: 01/05/2023]
Abstract
Sortase A (SrtA) anchors surface proteins to the cell wall and aids biofilm formation during infection, which functions as a key virulence factor of important Gram-positive pathogens, such as Staphylococcus aureus. At present researchers need a way in which to validate whether or not SrtA is a druggable target alternative to the conventional antibiotic targets in the mechanism. In this study, we performed a high-throughput screening and identified a new class of potential inhibitors of S. aureus SrtA, which are derived from natural products and contain the quinone skeleton. Compound 283 functions as an irreversible inhibitor that covalently alkylates the active site Cys184 of SrtA. NMR analysis confirms the direct interaction of the small-molecule inhibitor towards SrtA protein. The anchoring of protein A (SpA) to the cell wall and the biofilm formation are significantly attenuated when the S. aureus Newman strain is cultured in the presence of inhibitor. Our study indicates that compound 283 could be a potential hit for the development of new anti-virulence agents against S. aureus infections by covalently targeting SrtA.
Collapse
Affiliation(s)
- Xiaochen Hou
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China; University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Meining Wang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China
| | - Yi Wen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China
| | - Tengfeng Ni
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China
| | - Xiangna Guan
- Ministry of Education, School of Pharmacy, Fudan University, 826 ZhangHeng Road, Shanghai 201203, China
| | - Lefu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China
| | - Naixia Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China.
| | - Ao Zhang
- CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China.
| | - Cai-Guang Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 ZuChongZhi Road, Shanghai 201203, China.
| |
Collapse
|
17
|
El-Badry YAM, Sallam MS, El-Hashash MAA. Efficient 1,3,4-Thiadiazole-4,5-dihydropyridazin-3(2H)-ones as Antimicrobial Agents. Chem Pharm Bull (Tokyo) 2018; 66:427-433. [PMID: 29607908 DOI: 10.1248/cpb.c17-00918] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A set of novel series of 1,3,4-thiadiazolyl-sulfanyl-4,5-dihydropyridazin-3(2H)-ones with anticipated antimicrobial activity has been synthesized. The synthetic protocol of the targeted compounds was accomplished by treating β-aroylacrylic acid 1 with 5-amino-1,3,4-thiadiazole-2-thiol (2) to afford the thia-Michael adduct 3. Afterwards, the obtained thia-Michael adduct 3 was cyclized to 4,5-dihydropyridazin-3(2H)-ones 4a-d and the non-cyclized product hydrazone 5 by using different hydrazines. Moreover, adduct 3 was reacted with esters like diethyl malonate and ethyl acetoacetate affording 1,3,4-thiadiazolobutanamides 6a, b. Furthermore, the concurrent reaction of later butamides 6a, b with the hydrazine derivatives furnished thiadiazolopyridazin-3(2H)-ones 7a-d, 8, and butanoic acid 9.
Collapse
Affiliation(s)
- Yaser Abdel-Moemen El-Badry
- Organic Chemistry Lab., Faculty of Specific Education, Ain Shams University.,Organic Chemistry Dep., Faculty of Science, Taif University
| | | | | |
Collapse
|
18
|
Niu X, Gao Y, Yu Y, Yang Y, Wang G, Sun L, Wang H. Molecular Modelling reveals the inhibition mechanism and structure-activity relationship of curcumin and its analogues to Staphylococcal aureus Sortase A. J Biomol Struct Dyn 2018; 37:1220-1230. [PMID: 29546799 DOI: 10.1080/07391102.2018.1453380] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Previous studies found that the activity of Sortase A, a bacterial surface protein from Staphylococcus aureus, was inhibited by curcumin and its analogues. To explore this inhibitory mechanism, Sortase A and its inhibitors in complex systems were studied by molecular docking, molecular modelling, binding energy decomposition calculation and steered molecular dynamics simulations. Energy decomposition analysis indicated that PRO-163, LEU-169, GLN-172, ILE-182 and ILE-199 are key residues in Sortase A-inhibitor complexes. Furthermore, interactions between the methoxyl group on the benzene ring in the conjugated molecule (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and VAL-168, LEU-169 and GLN-172 induce the inhibitory activity based on the energy decomposition and distance analyses between the whole residues and inhibitors. However, because of its coiled structure, the non-conjugated molecule, tetrahydrocurcumin, with key residues in the binding sites of Sortase A, interacted weakly with SrtA, leading to the loss of inhibitory activity. Based on these results, the methoxyl group on the benzene ring in the conjugated molecule largely influenced the inhibitory activity of the Sortase A inhibitors.
Collapse
Affiliation(s)
- Xiaodi Niu
- a College of Food Science and Engineering , Jilin University , Changchun , China
| | - Yawen Gao
- a College of Food Science and Engineering , Jilin University , Changchun , China
| | - Yiding Yu
- a College of Food Science and Engineering , Jilin University , Changchun , China
| | - Yanan Yang
- a College of Food Science and Engineering , Jilin University , Changchun , China
| | - Guizhen Wang
- a College of Food Science and Engineering , Jilin University , Changchun , China
| | - Lin Sun
- a College of Food Science and Engineering , Jilin University , Changchun , China
| | - Hongsu Wang
- a College of Food Science and Engineering , Jilin University , Changchun , China
| |
Collapse
|
19
|
Cazelli DSP, Barroso MES, Pizi RB, Orlandi M, de Souza TB, Carvalho DT, da Silva Gonçalves A, Endringer DC. The relationship between the antimicrobial activity of eugenol and the LPETG peptide structure and associated analysis for docking purposes. CHEMICAL PAPERS 2017. [DOI: 10.1007/s11696-017-0181-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|