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Borges PHO, Ferreira SB, Silva FP. Recent Advances on Targeting Proteases for Antiviral Development. Viruses 2024; 16:366. [PMID: 38543732 PMCID: PMC10976044 DOI: 10.3390/v16030366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 02/21/2024] [Accepted: 02/24/2024] [Indexed: 05/23/2024] Open
Abstract
Viral proteases are an important target for drug development, since they can modulate vital pathways in viral replication, maturation, assembly and cell entry. With the (re)appearance of several new viruses responsible for causing diseases in humans, like the West Nile virus (WNV) and the recent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), understanding the mechanisms behind blocking viral protease's function is pivotal for the development of new antiviral drugs and therapeutical strategies. Apart from directly inhibiting the target protease, usually by targeting its active site, several new pathways have been explored to impair its activity, such as inducing protein aggregation, targeting allosteric sites or by inducing protein degradation by cellular proteasomes, which can be extremely valuable when considering the emerging drug-resistant strains. In this review, we aim to discuss the recent advances on a broad range of viral proteases inhibitors, therapies and molecular approaches for protein inactivation or degradation, giving an insight on different possible strategies against this important class of antiviral target.
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Affiliation(s)
- Pedro Henrique Oliveira Borges
- Laboratory of Organic Synthesis and Biological Prospecting, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil;
- Laboratory of Experimental and Computational Biochemistry of Drugs, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro 21040-900, Brazil
| | - Sabrina Baptista Ferreira
- Laboratory of Organic Synthesis and Biological Prospecting, Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro 21941-909, Brazil;
| | - Floriano Paes Silva
- Laboratory of Experimental and Computational Biochemistry of Drugs, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro 21040-900, Brazil
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2
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Naz S, Liu P, Farooq U, Ma H. Insight into de-regulation of amino acid feedback inhibition: a focus on structure analysis method. Microb Cell Fact 2023; 22:161. [PMID: 37612753 PMCID: PMC10464499 DOI: 10.1186/s12934-023-02178-z] [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: 06/07/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023] Open
Abstract
Regulation of amino acid's biosynthetic pathway is of significant importance to maintain homeostasis and cell functions. Amino acids regulate their biosynthetic pathway by end-product feedback inhibition of enzymes catalyzing committed steps of a pathway. Discovery of new feedback resistant enzyme variants to enhance industrial production of amino acids is a key objective in industrial biotechnology. Deregulation of feedback inhibition has been achieved for various enzymes using in vitro and in silico mutagenesis techniques. As enzyme's function, its substrate binding capacity, catalysis activity, regulation and stability are dependent on its structural characteristics, here, we provide detailed structural analysis of all feedback sensitive enzyme targets in amino acid biosynthetic pathways. Current review summarizes information regarding structural characteristics of various enzyme targets and effect of mutations on their structures and functions especially in terms of deregulation of feedback inhibition. Furthermore, applicability of various experimental as well as computational mutagenesis techniques to accomplish feedback resistance has also been discussed in detail to have an insight into various aspects of research work reported in this particular field of study.
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Affiliation(s)
- Sadia Naz
- Biodesign Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Pi Liu
- Biodesign Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China
| | - Umar Farooq
- Department of Chemistry, COMSATS University Islamabad, Abbottabad Campus, Islamabad, 22060, Pakistan
| | - Hongwu Ma
- Biodesign Center, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
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3
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Kretsch AM, Gadgil MG, DiCaprio AJ, Barrett SE, Kille BL, Si Y, Zhu L, Mitchell DA. Peptidase Activation by a Leader Peptide-Bound RiPP Recognition Element. Biochemistry 2023; 62:956-967. [PMID: 36734655 PMCID: PMC10126823 DOI: 10.1021/acs.biochem.2c00700] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The RiPP precursor recognition element (RRE) is a conserved domain found in many prokaryotic ribosomally synthesized and post-translationally modified peptide (RiPP) biosynthetic gene clusters (BGCs). RREs bind with high specificity and affinity to a recognition sequence within the N-terminal leader region of RiPP precursor peptides. Lasso peptide biosynthesis involves an RRE-dependent leader peptidase, which is discretely encoded or fused to the RRE as a di-domain protein. Here we leveraged thousands of predicted BGCs to define the RRE:leader peptidase interaction through evolutionary covariance analysis. Each interacting domain contributes a three-stranded β-sheet to form a hydrophobic β-sandwich-like interface. The bioinformatics-guided predictions were experimentally confirmed using proteins from discrete and fused lasso peptide BGC architectures. Support for the domain-domain interface derived from chemical shift perturbation, paramagnetic relaxation enhancement experiments, and rapid variant activity screening using cell-free biosynthesis. Further validation of selected variants was performed with purified proteins. We developed a p-nitroanilide-based leader peptidase assay to illuminate the role of RRE domains. Our data show that RRE domains play a dual function. RRE domains deliver the precursor peptide to the leader peptidase, and the rate is saturable as expected for a substrate. RRE domains also partially compose the elusive S2 proteolytic pocket that binds the penultimate threonine of lasso leader peptides. Because the RRE domain is required to form the active site, leader peptidase activity is greatly diminished when the RRE domain is supplied at substoichiometric levels. Full proteolytic activation requires RRE engagement with the recognition sequence-containing portion of the leader peptide. Together, our observations define a new mechanism for protease activity regulation.
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Affiliation(s)
- Ashley M. Kretsch
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Mayuresh G. Gadgil
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Adam J. DiCaprio
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Susanna E. Barrett
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Bryce L. Kille
- Department of Computer Science, Rice University, Houston, Texas, United States of America
| | - Yuanyuan Si
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
| | - Lingyang Zhu
- School of Chemical Sciences, NMR Laboratory, University of Illinois, Urbana, Illinois, United States of America
| | - Douglas A. Mitchell
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, United States of America
- Department of Chemistry, University of Illinois, Urbana, Illinois, United States of America
- Department of Microbiology, University of Illinois, Urbana, Illinois, United States of America
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4
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Qi J, Yao L. Modulators of neurolysin: promising agents for the treatment of tumor and neurological diseases. Med Chem Res 2021. [DOI: 10.1007/s00044-021-02761-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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5
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Oleoresins and naturally occurring compounds of Copaifera genus as antibacterial and antivirulence agents against periodontal pathogens. Sci Rep 2021; 11:4953. [PMID: 33654123 PMCID: PMC7925542 DOI: 10.1038/s41598-021-84480-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 02/03/2021] [Indexed: 01/31/2023] Open
Abstract
Invasion of periodontal tissues by Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans can be associated with aggressive forms of periodontitis. Oleoresins from different copaifera species and their compounds display various pharmacological properties. The present study evaluates the antibacterial and antivirulence activity of oleoresins obtained from different copaifera species and of ten isolated compounds against two causative agents of periodontitis. The following assays were performed: determination of the minimum inhibitory concentration (MIC), determination of the minimum bactericidal concentration (MBC), and determination of the antibiofilm activity by inhibition of biofilm formation and biofilm eradication tests. The antivirulence activity was assessed by hemagglutination, P. gingivalis Arg-X and Lis-X cysteine protease inhibition assay, and A. actinomycetemcomitans leukotoxin inhibition assay. The MIC and MBC of the oleoresins and isolated compounds 1, 2, and 3 ranged from 1.59 to 50 μg/mL against P. gingivalis (ATCC 33277) and clinical isolates and from 6.25 to 400 μg/mL against A. actinomycetemcomitans (ATCC 43717) and clinical isolates. About the antibiofilm activity, the oleoresins and isolated compounds 1, 2, and 3 inhibited biofilm formation by at least 50% and eradicated pre-formed P. gingivalis and A. actinomycetemcomitans biofilms in the monospecies and multispecies modes. A promising activity concerning cysteine protease and leucotoxin inhibition was also evident. In addition, molecular docking analysis was performed. The investigated oleoresins and their compounds may play an important role in the search for novel sources of agents that can act against periodontal pathogens.
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Purification and Biochemical Characterization of a New Protease Inhibitor from Conyza dioscoridis with Antimicrobial, Antifungal and Cytotoxic Effects. Molecules 2020; 25:molecules25225452. [PMID: 33233753 PMCID: PMC7699837 DOI: 10.3390/molecules25225452] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/22/2020] [Accepted: 11/17/2020] [Indexed: 11/26/2022] Open
Abstract
The main objective of the current study was the extraction, purification, and biochemical characterization of a protein protease inhibitor from Conyzadioscoridis. Antimicrobial potential and cytotoxic effects were also examined. The protease inhibitor was extracted in 0.1 M phosphate buffer (pH 6–7). Then, the protease inhibitor, named PDInhibitor, was purified using ammonium sulfate precipitation followed by filtration through a Sephadex G-50 column and had an apparent molecular weight of 25 kDa. The N-terminal sequence of PDInhibitor showed a high level of identity with those of the Kunitz family. PDInhibitor was found to be active at pH values ranging from 5.0 to 11.0, with maximal activity at pH 9.0. It was also fully active at 50 °C and maintained 90% of its stability at over 55 °C. The thermostability of the PDInhibitor was clearly enhanced by CaCl2 and sorbitol, whereas the presence of Ca2+ and Zn2+ ions, Sodium taurodeoxycholate (NaTDC), Sodium dodecyl sulfate (SDS), Dithiothreitol (DTT), and β-ME dramatically improved the inhibitory activity. A remarkable affinity of the protease inhibitor with available important therapeutic proteases (elastase and trypsin) was observed. PDInhibitor also acted as a potent inhibitor of commercial proteases from Aspergillus oryzae and of Proteinase K. The inhibitor displayed potent antimicrobial activity against gram+ and gram- bacteria and against fungal strains. Interestingly, PDInhibitor affected several human cancer cell lines, namely HCT-116, MDA-MB-231, and Lovo. Thus, it can be considered a potentially powerful therapeutic agent.
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Meng B, Lan K, Xie J, Lerner RA, Wilson IA, Yang B. Inhibitory antibodies identify unique sites of therapeutic vulnerability in rhinovirus and other enteroviruses. Proc Natl Acad Sci U S A 2020; 117:13499-13508. [PMID: 32467165 PMCID: PMC7306783 DOI: 10.1073/pnas.1918844117] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The existence of multiple serotypes renders vaccine development challenging for most viruses in the Enterovirus genus. An alternative and potentially more viable strategy for control of these viruses is to develop broad-spectrum antivirals by targeting highly conserved proteins that are indispensable for the virus life cycle, such as the 3C protease. Previously, two single-chain antibody fragments, YDF and GGVV, were reported to effectively inhibit human rhinovirus 14 proliferation. Here, we found that both single-chain antibody fragments target sites on the 3C protease that are distinct from its known drug site (peptidase active site) and possess different mechanisms of inhibition. YDF does not block the active site but instead noncompetitively inhibits 3C peptidase activity through an allosteric effect that is rarely seen for antibody protease inhibitors. Meanwhile, GGVV antagonizes the less-explored regulatory function of 3C in genome replication. The interaction between 3C and the viral genome 5' noncoding region has been reported to be important for enterovirus genome replication. Here, the interface between human rhinovirus 14 3C and its 5' noncoding region was probed by hydrogen-deuterium exchange coupled mass spectrometry and found to partially overlap with the interface between GGVV and 3C. Consistently, prebinding of GGVV completely abolishes interaction between human rhinovirus 14 3C and its 5' noncoding region. The epitopes of YDF and GGVV, therefore, represent two additional sites of therapeutic vulnerability in rhinovirus. Importantly, the GGVV epitope appears to be conserved across many enteroviruses, suggesting that it is a promising target for pan-enterovirus inhibitor screening and design.
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Affiliation(s)
- Bing Meng
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, People's Republic of China
| | - Keke Lan
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, People's Republic of China
- School of Life Science and Technology, ShanghaiTech University, 201210 Shanghai, People's Republic of China
| | - Jia Xie
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037
| | - Richard A Lerner
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037
| | - Ian A Wilson
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, People's Republic of China;
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037
- Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037
| | - Bei Yang
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, 201210 Shanghai, People's Republic of China;
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Afosah DK, Al-Horani RA. Sulfated Non-Saccharide Glycosaminoglycan Mimetics as Novel Drug Discovery Platform for Various Pathologies. Curr Med Chem 2020; 27:3412-3447. [PMID: 30457046 PMCID: PMC6551317 DOI: 10.2174/0929867325666181120101147] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 11/06/2018] [Accepted: 11/13/2018] [Indexed: 01/14/2023]
Abstract
Glycosaminoglycans (GAGs) are very complex, natural anionic polysaccharides. They are polymers of repeating disaccharide units of uronic acid and hexosamine residues. Owing to their template-free, spatiotemporally-controlled, and enzyme-mediated biosyntheses, GAGs possess enormous polydispersity, heterogeneity, and structural diversity which often translate into multiple biological roles. It is well documented that GAGs contribute to physiological and pathological processes by binding to proteins including serine proteases, serpins, chemokines, growth factors, and microbial proteins. Despite advances in the GAG field, the GAG-protein interface remains largely unexploited by drug discovery programs. Thus, Non-Saccharide Glycosaminoglycan Mimetics (NSGMs) have been rationally developed as a novel class of sulfated molecules that modulate GAG-protein interface to promote various biological outcomes of substantial benefit to human health. In this review, we describe the chemical, biochemical, and pharmacological aspects of recently reported NSGMs and highlight their therapeutic potentials as structurally and mechanistically novel anti-coagulants, anti-cancer agents, anti-emphysema agents, and anti-viral agents. We also describe the challenges that complicate their advancement and describe ongoing efforts to overcome these challenges with the aim of advancing the novel platform of NSGMs to clinical use.
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Affiliation(s)
- Daniel K. Afosah
- Department of Medicinal Chemistry and Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, Virginia 23219
| | - Rami A. Al-Horani
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, New Orleans, Louisiana 70125
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9
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Pant A, Kumar R, Wani NA, Verma S, Sharma R, Pande V, Saxena AK, Dixit R, Rai R, Pandey KC. Allosteric Site Inhibitor Disrupting Auto-Processing of Malarial Cysteine Proteases. Sci Rep 2018; 8:16193. [PMID: 30385827 PMCID: PMC6212536 DOI: 10.1038/s41598-018-34564-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 10/16/2018] [Indexed: 02/08/2023] Open
Abstract
Falcipains are major haemoglobinases of Plasmodium falciparum required for parasite growth and development. They consist of pro- and mature domains that interact via 'hot-spot' interactions and maintain the structural integrity of enzyme in zymogen state. Upon sensing the acidic environment, these interactions dissociate and active enzyme is released. For inhibiting falcipains, several active site inhibitors exist, however, compounds that target via allosteric mechanism remains uncharacterized. Therefore, we designed and synthesized six azapeptide compounds, among which, NA-01 & NA-03 arrested parasite growth by specifically blocking the auto-processing of falcipains. Inhibitors showed high affinity for enzymes in presence of the prodomain without affecting the secondary structure. Binding of NA-03 at the interface induced rigidity in the prodomain preventing structural reorganization. We further reported a histidine-dependent activation of falcipain. Collectively, for the first time we provide a framework for blocking the allosteric site of crucial haemoglobinases of the human malaria parasite. Targeting the allosteric site could provide high selectivity and less vulnerable to drug resistance.
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Affiliation(s)
- A Pant
- ICMR-National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand, India
| | - R Kumar
- Integrated Science Lab, Umeå University, Umeå, Sweden
| | - N A Wani
- Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, India
| | - S Verma
- ICMR-National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand, India
| | - R Sharma
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - V Pande
- Department of Biotechnology, Kumaun University, Nainital, Uttarakhand, India
| | - A K Saxena
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - R Dixit
- ICMR-National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India
| | - R Rai
- Medicinal Chemistry Division, CSIR-Indian Institute of Integrative Medicine, Jammu, India
| | - K C Pandey
- ICMR-National Institute of Malaria Research, Dwarka Sector 8, New Delhi, India.
- Department of Biochemistry, ICMR-National Institute for Research in Environmental Health, Bhopal, MP - 462001, India.
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Nabi M, Bhat A, Abeer Rasool SU, Ashraf S, Maqbool R, Ahmad Ganie S, Amin S. Physio-chemical Characterization and Anti-microbial Activity of Serine Protease Inhibitors Purified from the Sophora japonica Seeds. Pak J Biol Sci 2018; 21:432-440. [PMID: 30724044 DOI: 10.3923/pjbs.2018.432.440] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND OBJECTIVE Protease inhibitors (PIs) regulate various cellular processes like cell cycle, differentiation, apoptosis and immune responses. Leguminous seeds are rich sources of protease inhibitors and many novel protease inhibitors have been purified from them. To isolate and purify protease inhibitors from seeds of Sophora japonica, characterize and investigate their anti- microbial activity. MATERIALS AND METHODS Protease inhibitors (SJ-pi I and SJ-pi II) were purified to homogeneity by ammonium sulfate precipitation, Ion exchange chromatography and column chromatography. The molecular mass was estimated by size exclusion chromatography and by SDS-PAGE and anti- microbial activity was tested by agar disk diffusion method. RESULTS Two protease inhibitors were isolated and purified from Sophora japonica seeds, SJ-pi I and SJ-pi II, with molecular weight of 15.1 and 31 kDa, respectively. Both purified inhibitors were active over a range of pH (6.0-9.0) and showed maximum activity in the temperature range of 30-40°C. They inhibited the growth of three Gram-positive bacteria. CONCLUSION Protease inhibitors were classified as serine protease inhibitors, however further necessary structural investigations need to be carried out so as to group them into specific class of serine protease inhibitors.
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Chandrasekaran R, Lacy DB. The role of toxins in Clostridium difficile infection. FEMS Microbiol Rev 2017; 41:723-750. [PMID: 29048477 PMCID: PMC5812492 DOI: 10.1093/femsre/fux048] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 10/10/2017] [Indexed: 02/06/2023] Open
Abstract
Clostridium difficile is a bacterial pathogen that is the leading cause of nosocomial antibiotic-associated diarrhea and pseudomembranous colitis worldwide. The incidence, severity, mortality and healthcare costs associated with C. difficile infection (CDI) are rising, making C. difficile a major threat to public health. Traditional treatments for CDI involve use of antibiotics such as metronidazole and vancomycin, but disease recurrence occurs in about 30% of patients, highlighting the need for new therapies. The pathogenesis of C. difficile is primarily mediated by the actions of two large clostridial glucosylating toxins, toxin A (TcdA) and toxin B (TcdB). Some strains produce a third toxin, the binary toxin C. difficile transferase, which can also contribute to C. difficile virulence and disease. These toxins act on the colonic epithelium and immune cells and induce a complex cascade of cellular events that result in fluid secretion, inflammation and tissue damage, which are the hallmark features of the disease. In this review, we summarize our current understanding of the structure and mechanism of action of the C. difficile toxins and their role in disease.
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Affiliation(s)
- Ramyavardhanee Chandrasekaran
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - D. Borden Lacy
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
- The Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37232, USA
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Torres L, Krüger A, Csibra E, Gianni E, Pinheiro VB. Synthetic biology approaches to biological containment: pre-emptively tackling potential risks. Essays Biochem 2016; 60:393-410. [PMID: 27903826 PMCID: PMC5264511 DOI: 10.1042/ebc20160013] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 10/21/2016] [Accepted: 10/24/2016] [Indexed: 12/29/2022]
Abstract
Biocontainment comprises any strategy applied to ensure that harmful organisms are confined to controlled laboratory conditions and not allowed to escape into the environment. Genetically engineered microorganisms (GEMs), regardless of the nature of the modification and how it was established, have potential human or ecological impact if accidentally leaked or voluntarily released into a natural setting. Although all evidence to date is that GEMs are unable to compete in the environment, the power of synthetic biology to rewrite life requires a pre-emptive strategy to tackle possible unknown risks. Physical containment barriers have proven effective but a number of strategies have been developed to further strengthen biocontainment. Research on complex genetic circuits, lethal genes, alternative nucleic acids, genome recoding and synthetic auxotrophies aim to design more effective routes towards biocontainment. Here, we describe recent advances in synthetic biology that contribute to the ongoing efforts to develop new and improved genetic, semantic, metabolic and mechanistic plans for the containment of GEMs.
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Affiliation(s)
- Leticia Torres
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K.
| | - Antje Krüger
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
| | - Eszter Csibra
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
| | - Edoardo Gianni
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K
| | - Vitor B Pinheiro
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, U.K.
- Birkbeck, Department of Biological Sciences, University of London, Malet Street, WC1E 7HX, U.K
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Allosteric Partial Inhibition of Monomeric Proteases. Sulfated Coumarins Induce Regulation, not just Inhibition, of Thrombin. Sci Rep 2016; 6:24043. [PMID: 27053426 PMCID: PMC4823711 DOI: 10.1038/srep24043] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Accepted: 03/14/2016] [Indexed: 11/26/2022] Open
Abstract
Allosteric partial inhibition of soluble, monomeric proteases can offer major regulatory advantages, but remains a concept on paper to date; although it has been routinely documented for receptors and oligomeric proteins. Thrombin, a key protease of the coagulation cascade, displays significant conformational plasticity, which presents an attractive opportunity to discover small molecule probes that induce sub-maximal allosteric inhibition. We synthesized a focused library of some 36 sulfated coumarins to discover two agents that display sub-maximal efficacy (~50%), high potency (<500 nM) and high selectivity for thrombin (>150-fold). Michaelis-Menten, competitive inhibition, and site-directed mutagenesis studies identified exosite 2 as the site of binding for the most potent sulfated coumarin. Stern-Volmer quenching of active site-labeled fluorophore suggested that the allosteric regulators induce intermediate structural changes in the active site as compared to those that display ~80–100% efficacy. Antithrombin inactivation of thrombin was impaired in the presence of the sulfated coumarins suggesting that allosteric partial inhibition arises from catalytic dysfunction of the active site. Overall, sulfated coumarins represent first-in-class, sub-maximal inhibitors of thrombin. The probes establish the concept of allosteric partial inhibition of soluble, monomeric proteins. This concept may lead to a new class of anticoagulants that are completely devoid of bleeding.
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Zhang W, Zhai L, Lu W, Boohaker RJ, Padmalayam I, Li Y. Discovery of Novel Allosteric Eg5 Inhibitors Through Structure-Based Virtual Screening. Chem Biol Drug Des 2016; 88:178-87. [PMID: 26864917 DOI: 10.1111/cbdd.12744] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 12/08/2015] [Accepted: 01/31/2016] [Indexed: 12/11/2022]
Abstract
Mitotic kinesin Eg5 is an attractive anticancer drug target. Discovery of Eg5 inhibitors has been focused on targeting the 'monastrol-binding site'. However, acquired drug resistance has been reported for such inhibitors. Therefore, identifying new Eg5 inhibitors which function through a different mechanism(s) could complement current drug candidates and improve drug efficacy. In this study, we explored a novel allosteric site of Eg5 and identified new Eg5 inhibitors through structure-based virtual screening. Experiments with the saturation-transfer difference NMR demonstrated that the identified Eg5 inhibitor SRI35566 binds directly to Eg5 without involving microtubules. Moreover, SRI35566 and its two analogs significantly induced monopolar spindle formation in colorectal cancer HCT116 cells and suppressed cancer cell viability and colony formation. Together, our findings reveal a new allosteric regulation mechanism of Eg5 and a novel drug targeting site for cancer therapy.
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Affiliation(s)
- Wei Zhang
- Drug Discovery Division, Southern Research Institute, 2000 9th Avenue South, Birmingham, AL, USA
| | - Ling Zhai
- Drug Discovery Division, Southern Research Institute, 2000 9th Avenue South, Birmingham, AL, USA
| | - Wenyan Lu
- Drug Discovery Division, Southern Research Institute, 2000 9th Avenue South, Birmingham, AL, USA
| | - Rebecca J Boohaker
- Drug Discovery Division, Southern Research Institute, 2000 9th Avenue South, Birmingham, AL, USA
| | - Indira Padmalayam
- Drug Discovery Division, Southern Research Institute, 2000 9th Avenue South, Birmingham, AL, USA
| | - Yonghe Li
- Drug Discovery Division, Southern Research Institute, 2000 9th Avenue South, Birmingham, AL, USA
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15
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Matsuo T, Yamada K, Ishida M, Miura Y, Yamanaka M, Hirota S. Effect of a Procaspase-Activating Compound on the Catalytic Activity of Mature Caspase-3. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2015. [DOI: 10.1246/bcsj.20150139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Takashi Matsuo
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST)
| | - Keita Yamada
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST)
| | - Masaya Ishida
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST)
| | - Yoshiyuki Miura
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST)
| | - Masaru Yamanaka
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST)
| | - Shun Hirota
- Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST)
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16
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Abstract
Accurate identification of drug targets is a crucial part of any drug development program. We mined the human proteome to discover properties of proteins that may be important in determining their suitability for pharmaceutical modulation. Data was gathered concerning each protein's sequence, post-translational modifications, secondary structure, germline variants, expression profile and drug target status. The data was then analysed to determine features for which the target and non-target proteins had significantly different values. This analysis was repeated for subsets of the proteome consisting of all G-protein coupled receptors, ion channels, kinases and proteases, as well as proteins that are implicated in cancer. Machine learning was used to quantify the proteins in each dataset in terms of their potential to serve as a drug target. This was accomplished by first inducing a random forest that could distinguish between its targets and non-targets, and then using the random forest to quantify the drug target likeness of the non-targets. The properties that can best differentiate targets from non-targets were primarily those that are directly related to a protein's sequence (e.g. secondary structure). Germline variants, expression levels and interactions between proteins had minimal discriminative power. Overall, the best indicators of drug target likeness were found to be the proteins' hydrophobicities, in vivo half-lives, propensity for being membrane bound and the fraction of non-polar amino acids in their sequences. In terms of predicting potential targets, datasets of proteases, ion channels and cancer proteins were able to induce random forests that were highly capable of distinguishing between targets and non-targets. The non-target proteins predicted to be targets by these random forests comprise the set of the most suitable potential future drug targets, and should therefore be prioritised when building a drug development programme.
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Affiliation(s)
- Simon C. Bull
- Manchester Institute of Biotechnology, Faculty of Life Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kigndom
| | - Andrew J. Doig
- Manchester Institute of Biotechnology, Faculty of Life Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kigndom
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17
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Katoch R, Singh SK, Thakur N, Dutt S, Yadav SK, Shukle R. Cloning, characterization, expression analysis and inhibition studies of a novel gene encoding Bowman–Birk type protease inhibitor from rice bean. Gene 2014; 546:342-51. [DOI: 10.1016/j.gene.2014.05.055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/21/2014] [Accepted: 05/23/2014] [Indexed: 10/25/2022]
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18
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Udi Y, Fragai M, Grossman M, Mitternacht S, Arad-Yellin R, Calderone V, Melikian M, Toccafondi M, Berezovsky IN, Luchinat C, Sagi I. Unraveling Hidden Regulatory Sites in Structurally Homologous Metalloproteases. J Mol Biol 2013; 425:2330-46. [DOI: 10.1016/j.jmb.2013.04.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 04/05/2013] [Accepted: 04/05/2013] [Indexed: 01/26/2023]
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19
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N-acetyl cysteine as an osteogenesis-enhancing molecule for bone regeneration. Biomaterials 2013; 34:6147-56. [PMID: 23711675 DOI: 10.1016/j.biomaterials.2013.04.064] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 04/30/2013] [Indexed: 12/31/2022]
Abstract
Bone regeneration often requires cues from osteogenesis-inducing factors for successful outcome. N-acetyl cysteine (NAC), an anti-oxidant small molecule, possibly modulates osteoblastic differentiation. This study investigated the potential of NAC as an osteogenesis-enhancing molecule in vitro and in vivo. Various concentrations of NAC (0, 2.5, 5.0, and 10 mM) were added to rat bone marrow stromal cell or osteoblastic cell culture in media with or without dexamethasone. The results showed marked enhancement of alkaline phosphatase activity and mineralized matrix formation together with consistent upregulation of bone-related gene markers such as collagen I, osteopontin, and osteocalcin in the osteoblastic culture with addition of 2.5 or 5.0 mM NAC regardless of the presence of dexamethasone. Micro-CT-based analysis and histological observation revealed that addition of NAC to a collagenous sponge implanted in a critical size cortical bone defect (3.0 mm × 5.0 mm) in rat femur yielded acceleration and completion of defect closure, with thick, compact, and contiguous bone after 6 weeks of healing. In contrast, with sponge alone, only sparse and incomplete bone regeneration was observed during the matching healing period. These results indicate that NAC can function as an osteogenesis-enhancing molecule to accelerate bone regeneration by activating differentiation of osteogenic lineages.
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20
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Berezovsky IN. Thermodynamics of allostery paves a way to allosteric drugs. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:830-5. [PMID: 23376182 DOI: 10.1016/j.bbapap.2013.01.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Revised: 01/16/2013] [Accepted: 01/21/2013] [Indexed: 12/30/2022]
Abstract
We overview here our recent work on the thermodynamic view of allosteric regulation and communication. Starting from the geometry-based prediction of regulatory binding sites in a static structure, we move on to exploring a connection between ligand binding and the intrinsic dynamics of the protein molecule. We describe here two recently introduced measures, binding leverage and leverage coupling, which allow one to analyze the molecular basis of allosteric regulation. We discuss the advantages of these measures and show that they work universally in proteins of different sizes, oligomeric states, and functions. We also point the problems that have to be solved before completing an atomic level description of allostery, and briefly discuss ideas for computational design of allosteric drugs. This article is part of a Special Issue entitled: The emerging dynamic view of proteins: Protein plasticity in allostery, evolution and self-assembly.
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Affiliation(s)
- Igor N Berezovsky
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot 76100, Israel.
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21
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Merdanovic M, Mönig T, Ehrmann M, Kaiser M. Diversity of allosteric regulation in proteases. ACS Chem Biol 2013. [PMID: 23181429 DOI: 10.1021/cb3005935] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Allostery is a fundamental regulatory mechanism that is based on a functional modulation of a site by a distant site. Allosteric regulation can be triggered by binding of diverse allosteric effectors, ranging from small molecules to macromolecules, and is therefore offering promising opportunities for functional modulation in a wide range of applications including the development of chemical probes or drug discovery. Here, we provide an overview of key classes of allosteric protease effectors, their corresponding molecular mechanisms, and their practical implications.
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Affiliation(s)
- Melisa Merdanovic
- Department of Microbiology
II and ‡Department
of Chemical Biology, Center for Medical Biotechnology,
Faculty of Biology, University of Duisburg-Essen, Universtitätsstr.
2, 45117 Essen, Germany
| | - Timon Mönig
- Department of Microbiology
II and ‡Department
of Chemical Biology, Center for Medical Biotechnology,
Faculty of Biology, University of Duisburg-Essen, Universtitätsstr.
2, 45117 Essen, Germany
| | - Michael Ehrmann
- Department of Microbiology
II and ‡Department
of Chemical Biology, Center for Medical Biotechnology,
Faculty of Biology, University of Duisburg-Essen, Universtitätsstr.
2, 45117 Essen, Germany
| | - Markus Kaiser
- Department of Microbiology
II and ‡Department
of Chemical Biology, Center for Medical Biotechnology,
Faculty of Biology, University of Duisburg-Essen, Universtitätsstr.
2, 45117 Essen, Germany
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22
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Gottschalk RA, Martins AJ, Sjoelund V, Angermann BR, Lin B, Germain RN. Recent progress using systems biology approaches to better understand molecular mechanisms of immunity. Semin Immunol 2012; 25:201-8. [PMID: 23238271 DOI: 10.1016/j.smim.2012.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 11/08/2012] [Indexed: 01/06/2023]
Abstract
The immune system is composed of multiple dynamic molecular and cellular networks, the complexity of which has been revealed by decades of exacting reductionist research. However, understanding of the immune system sufficient to anticipate its response to novel perturbations requires a more integrative or systems approach to immunology. While methods for unbiased high-throughput data acquisition and computational integration of the resulting datasets are still relatively new, they have begun to substantially enhance our understanding of immunological phenomena. Such approaches have expanded our view of interconnected signaling and transcriptional networks and have highlighted the function of non-linear processes such as spatial regulation and feedback loops. In addition, advances in single cell measurement technology have demonstrated potential sources and functions of response heterogeneity in system behavior. The success of the studies reviewed here often depended upon integration of one or more systems biology approaches with more traditional methods. We hope these examples will inspire a broader range of immunologists to probe questions in a quantitative and integrated manner, advancing collective efforts to understand the immune "system".
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Affiliation(s)
- Rachel A Gottschalk
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Andrew J Martins
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Virginie Sjoelund
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Bastian R Angermann
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Bin Lin
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
| | - Ronald N Germain
- Laboratory of Systems Biology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892 USA
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23
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Majmudar CY, Højfeldt JW, Arevang CJ, Pomerantz WC, Gagnon JK, Schultz PJ, Cesa LC, Doss CH, Rowe SP, Vásquez V, Tamayo-Castillo G, Cierpicki T, Brooks CL, Sherman DH, Mapp AK. Sekikaic Acid and Lobaric Acid Target a Dynamic Interface of the Coactivator CBP/p300. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201206815] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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24
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Majmudar CY, Højfeldt JW, Arevang CJ, Pomerantz WC, Gagnon JK, Schultz PJ, Cesa LC, Doss CH, Rowe SP, Vásquez V, Tamayo-Castillo G, Cierpicki T, Brooks CL, Sherman DH, Mapp AK. Sekikaic acid and lobaric acid target a dynamic interface of the coactivator CBP/p300. Angew Chem Int Ed Engl 2012; 51:11258-62. [PMID: 23042634 DOI: 10.1002/anie.201206815] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Indexed: 12/25/2022]
Abstract
Capturing a coactivator, naturally: the natural products sekikaic acid and lobaric acid, isolated after a high-throughput screen of a structurally diverse extract collection, effectively target the dynamic binding interfaces of the GACKIX domain of the coactivator CBP/p300. These molecules are the most effective inhibitors of the GACKIX domain yet described and are uniquely selective for this domain.
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25
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Zorn JA, Wolan DW, Agard NJ, Wells JA. Fibrils colocalize caspase-3 with procaspase-3 to foster maturation. J Biol Chem 2012; 287:33781-95. [PMID: 22872644 DOI: 10.1074/jbc.m112.386128] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Most proteases are expressed as inactive precursors, or zymogens, that become activated by limited proteolysis. We previously identified a small molecule, termed 1541, that dramatically promotes the maturation of the zymogen, procaspase-3, to its mature form, caspase-3. Surprisingly, compound 1541 self-assembles into nanofibrils, and localization of procaspase-3 to the fibrils promotes activation. Here, we interrogate the biochemical mechanism of procaspase-3 activation on 1541 fibrils in addition to proteogenic amyloid-β(1-40) fibrils. In contrast to previous reports, we find no evidence that procaspase-3 alone is capable of self-activation, consistent with its fate-determining role in executing apoptosis. In fact, mature caspase-3 is >10(7)-fold more active than procaspase-3, making this proenzyme a remarkably inactive zymogen. However, we also show that fibril-induced colocalization of trace amounts of caspase-3 or other initiator proteases with procaspase-3 dramatically stimulates maturation of the proenzyme in vitro. Thus, similar to known cellular signaling complexes, these synthetic or natural fibrils can serve as platforms to concentrate procaspase-3 for trans-activation by upstream proteases.
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Affiliation(s)
- Julie A Zorn
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, USA
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26
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Qi Y, Wang Q, Tang B, Lai L. Identifying Allosteric Binding Sites in Proteins with a Two-State Go̅ Model for Novel Allosteric Effector Discovery. J Chem Theory Comput 2012; 8:2962-71. [DOI: 10.1021/ct300395h] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Yifei Qi
- BNLMS,
State Key Laboratory for Structural Chemistry of Unstable and Stable
Species, and Peking−Tsinghua Center for Life Sciences at College
of Chemistry and Molecular Engineering and ‡Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Qian Wang
- BNLMS,
State Key Laboratory for Structural Chemistry of Unstable and Stable
Species, and Peking−Tsinghua Center for Life Sciences at College
of Chemistry and Molecular Engineering and ‡Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Bo Tang
- BNLMS,
State Key Laboratory for Structural Chemistry of Unstable and Stable
Species, and Peking−Tsinghua Center for Life Sciences at College
of Chemistry and Molecular Engineering and ‡Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Luhua Lai
- BNLMS,
State Key Laboratory for Structural Chemistry of Unstable and Stable
Species, and Peking−Tsinghua Center for Life Sciences at College
of Chemistry and Molecular Engineering and ‡Center for Quantitative Biology, Peking University, Beijing 100871, China
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27
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Mijakovic I, Macek B. Impact of phosphoproteomics on studies of bacterial physiology. FEMS Microbiol Rev 2012; 36:877-92. [DOI: 10.1111/j.1574-6976.2011.00314.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 10/21/2011] [Accepted: 10/22/2011] [Indexed: 11/27/2022] Open
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28
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Pruitt RN, Lacy DB. Toward a structural understanding of Clostridium difficile toxins A and B. Front Cell Infect Microbiol 2012; 2:28. [PMID: 22919620 PMCID: PMC3417631 DOI: 10.3389/fcimb.2012.00028] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 02/27/2012] [Indexed: 12/17/2022] Open
Abstract
Clostridium difficile is a toxin-producing bacterium that is a frequent cause of hospital-acquired and antibiotic-associated diarrhea. The incidence, severity, and costs associated with C. difficile associated disease are substantial and increasing, making C. difficile a significant public health concern. The two primary toxins, TcdA and TcdB, disrupt host cell function by inactivating small GTPases that regulate the actin cytoskeleton. This review will discuss the role of these two toxins in pathogenesis and the structural and molecular mechanisms by which they intoxicate cells. A focus will be placed on recent publications highlighting mechanistic similarities and differences between TcdA, TcdB, and different TcdB variants.
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Affiliation(s)
- Rory N Pruitt
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville TN, USA
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29
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Shen A. Clostridium difficile toxins: mediators of inflammation. J Innate Immun 2012; 4:149-58. [PMID: 22237401 DOI: 10.1159/000332946] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Accepted: 09/06/2011] [Indexed: 12/18/2022] Open
Abstract
Clostridium difficile is a significant problem in hospital settings as the most common cause of nosocomial diarrhea worldwide. C. difficile infections (CDIs) are characterized by an acute intestinal inflammatory response with neutrophil infiltration. These symptoms are primarily caused by the glucosylating toxins, TcdA and TcdB. In the past decade, the frequency and severity of CDIs have increased markedly due to the emergence of so-called hypervirulent strains that overproduce cytotoxic glucosylating toxins relative to historical strains. In addition, these strains produce a third toxin, binary toxin or C. difficile transferase (CDT), that may contribute to hypervirulence. Both the glucosylating toxins and CDT covalently modify target cell proteins to cause disassembly of the actin cytoskeleton and induce severe inflammation. This review summarizes our current knowledge of the mechanisms by which glucosylating toxins and CDT disrupt target cell function, alter host physiology and stimulate immune responses.
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Affiliation(s)
- Aimee Shen
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vt. 05401, USA.
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30
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Deu E, Verdoes M, Bogyo M. New approaches for dissecting protease functions to improve probe development and drug discovery. Nat Struct Mol Biol 2012; 19:9-16. [PMID: 22218294 DOI: 10.1038/nsmb.2203] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Proteases are well-established targets for pharmaceutical development because of their known enzymatic mechanism and their regulatory roles in many pathologies. However, many potent clinical lead compounds have been unsuccessful either because of a lack of specificity or because of our limited understanding of the biological roles of the targeted protease. In order to successfully develop protease inhibitors as drugs, it is necessary to understand protease functions and to expand the platform of inhibitor development beyond active site-directed design and in vitro optimization. Several newly developed technologies will enhance assessment of drug selectivity in living cells and animal models, allowing researchers to focus on compounds with high specificity and minimal side effects in vivo. In this review, we highlight advances in the development of chemical probes, proteomic methods and screening tools that we feel will help facilitate this paradigm shift in drug discovery.
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Affiliation(s)
- Edgar Deu
- Department of Pathology, Stanford University School of Medicine, Stanford, California, USA
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31
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Derouiche A, Cousin C, Mijakovic I. Protein phosphorylation from the perspective of systems biology. Curr Opin Biotechnol 2011; 23:585-90. [PMID: 22119098 DOI: 10.1016/j.copbio.2011.11.008] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 11/06/2011] [Indexed: 10/15/2022]
Abstract
Protein phosphorylation pathways emerge as large and interconnected networks, involving mutually activating protein kinases, kinases acting as network nodes by phosphorylating different substrates, and cross-talk of phosphorylation with other post-translational modifications. The complexity of these networks clearly necessitates the use of systems biology approaches. Phosphoproteomics represents the basis for detection of phosphoproteins and phosphorylation sites, but it must be combined with transcriptomics and interactomics in attempts to build in silico phosphorylation networks. This review highlights the implication of phosphorylation in cellular physiology across all domains of life. It focuses particularly on reports of human disease correlated to defects in phosphorylation networks. Brief outline of developments in quantitative mass spectrometry-based proteomics and bioinformatic tools specific for phosphoproteome studies is provided.
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32
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Zorn JA, Wille H, Wolan DW, Wells JA. Self-assembling small molecules form nanofibrils that bind procaspase-3 to promote activation. J Am Chem Soc 2011; 133:19630-3. [PMID: 22066605 DOI: 10.1021/ja208350u] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Modulating enzyme function with small-molecule activators, as opposed to inhibitors, offers new opportunities for drug discovery and allosteric regulation. We previously identified a compound, called 1541, from a high-throughput screen (HTS) that stimulates activation of a proenzyme, procaspase-3, to generate mature caspase-3. Here we further investigate the mechanism of activation and report the surprising finding that 1541 self-assembles into nanofibrils exceeding 1 μm in length. These particles are an unanticipated outcome from an HTS that have properties distinct from standard globular protein aggregators. Moreover, 1541 nanofibrils function as a unique biocatalytic material that activates procaspase-3 via induced proximity. These studies demonstrate a novel approach for proenzyme activation through binding to fibrils, which may mimic how procaspases are naturally processed on protein scaffolds.
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Affiliation(s)
- Julie A Zorn
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California, USA
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33
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Häcker HG, Sisay MT, Gütschow M. Allosteric modulation of caspases. Pharmacol Ther 2011; 132:180-95. [DOI: 10.1016/j.pharmthera.2011.07.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 06/15/2011] [Indexed: 12/19/2022]
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34
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Rational design of inhibitors and activity-based probes targeting Clostridium difficile virulence factor TcdB. ACTA ACUST UNITED AC 2011; 17:1201-11. [PMID: 21095570 DOI: 10.1016/j.chembiol.2010.09.011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 09/30/2010] [Accepted: 09/30/2010] [Indexed: 01/05/2023]
Abstract
Clostridium difficile is a leading cause of nosocomial infections. The major virulence factors of this pathogen are the multi-domain toxins TcdA and TcdB. These toxins contain a cysteine protease domain (CPD) that autoproteolytically releases a cytotoxic effector domain upon binding intracellular inositol hexakisphosphate. Currently, there are no known inhibitors of this protease. Here, we describe the rational design of covalent small molecule inhibitors of TcdB CPD. We identified compounds that inactivate TcdB holotoxin function in cells and solved the structure of inhibitor-bound protease to 2.0 Å. This structure reveals the molecular basis of CPD substrate recognition and informed the synthesis of activity-based probes for this enzyme. The inhibitors presented will guide the development of therapeutics targeting C. difficile, and the probes will serve as tools for studying the unique activation mechanism of bacterial toxin CPDs.
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35
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Defining an allosteric circuit in the cysteine protease domain of Clostridium difficile toxins. Nat Struct Mol Biol 2011; 18:364-71. [PMID: 21317893 PMCID: PMC3076311 DOI: 10.1038/nsmb.1990] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 11/24/2010] [Indexed: 01/04/2023]
Abstract
An internal cysteine protease domain (CPD) autoproteolytically regulates Clostridium difficile glucosylating toxins by releasing a cytotoxic effector domain into target cells. CPD activity is itself allosterically regulated by the eukaryotic-specific molecule inositol hexakisphosphate (InsP6). Although allostery controls the function of most proteins, the molecular details underlying this regulatory mechanism are often difficult to characterize. Here we use chemical probes to show that apo-CPD is in dynamic equilibrium between active and inactive states. InsP6 dramatically shifts this equilibrium towards an active conformer that is further restrained upon binding a suicide substrate. Structural analyses combined with systematic mutational and disulfide bond engineering studies reveal that residues within a β-hairpin region functionally couple the InsP6 binding site to the active site. Collectively, our results identify an allosteric circuit that allows bacterial virulence factors to sense and respond to the eukaryotic environment.
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