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Meek RW, Cadby IT, Lovering AL. Bdellovibrio bacteriovorus phosphoglucose isomerase structures reveal novel rigidity in the active site of a selected subset of enzymes upon substrate binding. Open Biol 2021; 11:210098. [PMID: 34375548 PMCID: PMC8354745 DOI: 10.1098/rsob.210098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Glycolysis and gluconeogenesis are central pathways of metabolism across all domains of life. A prominent enzyme in these pathways is phosphoglucose isomerase (PGI), which mediates the interconversion of glucose-6-phosphate and fructose-6-phosphate. The predatory bacterium Bdellovibrio bacteriovorus leads a complex life cycle, switching between intraperiplasmic replicative and extracellular 'hunter' attack-phase stages. Passage through this complex life cycle involves different metabolic states. Here we present the unliganded and substrate-bound structures of the B. bacteriovorus PGI, solved to 1.74 Å and 1.67 Å, respectively. These structures reveal that an induced-fit conformational change within the active site is not a prerequisite for the binding of substrates in some PGIs. Crucially, we suggest a phenylalanine residue, conserved across most PGI enzymes but substituted for glycine in B. bacteriovorus and other select organisms, is central to the induced-fit mode of substrate recognition for PGIs. This enzyme also represents the smallest conventional PGI characterized to date and probably represents the minimal requirements for a functional PGI.
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Affiliation(s)
- R W Meek
- York Structural Biology Laboratory, Department of Chemistry, University of York, York YO10 5DD, UK
| | - I T Cadby
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - A L Lovering
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
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Jeffery CJ, Dorgan KM, Pysh L. Promoting a more integrated approach to structure and function. Integr Comp Biol 2021; 61:2020-2030. [PMID: 34180524 DOI: 10.1093/icb/icab144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The connection between structure and function is one of the fundamental tenets of biology: a biological unit's structure determines its function, and, conversely, its function depends upon its structure. Historically, important advances have been made either when understanding of structure leads to questions about function or when understanding of function raises questions about the structures involved. Consequently, considering the connections between structure and function from a broader perspective might lead to the development of novel hypotheses that move our understanding of the fundamental connections between structure and function forward. Better integration of structure and function is a key component in the broader goal of reintegrating biology within and across scales. Here, we provide examples of how integrating studies of structure and function as well as comparing structure-function relationships across biological scales can lead to scientific advances. We also emphasize the potential of integrating studies of structure and function across scales for bio-inspired design and for improving biology education.
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Affiliation(s)
- Constance J Jeffery
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | | | - Leonard Pysh
- Biology Department, Roanoke College, Salem, VA, 24153, USA
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Sampaio Guther ML, Prescott AR, Kuettel S, Tinti M, Ferguson MAJ. Nucleotide sugar biosynthesis occurs in the glycosomes of procyclic and bloodstream form Trypanosoma brucei. PLoS Negl Trop Dis 2021; 15:e0009132. [PMID: 33592041 PMCID: PMC7909634 DOI: 10.1371/journal.pntd.0009132] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 02/26/2021] [Accepted: 01/12/2021] [Indexed: 11/19/2022] Open
Abstract
In Trypanosoma brucei, there are fourteen enzymatic biotransformations that collectively convert glucose into five essential nucleotide sugars: UDP-Glc, UDP-Gal, UDP-GlcNAc, GDP-Man and GDP-Fuc. These biotransformations are catalyzed by thirteen discrete enzymes, five of which possess putative peroxisome targeting sequences. Published experimental analyses using immunofluorescence microscopy and/or digitonin latency and/or subcellular fractionation and/or organelle proteomics have localized eight and six of these enzymes to the glycosomes of bloodstream form and procyclic form T. brucei, respectively. Here we increase these glycosome localizations to eleven in both lifecycle stages while noting that one, phospho-N-acetylglucosamine mutase, also localizes to the cytoplasm. In the course of these studies, the heterogeneity of glycosome contents was also noted. These data suggest that, unlike other eukaryotes, all of nucleotide sugar biosynthesis in T. brucei is compartmentalized to the glycosomes in both lifecycle stages. The implications are discussed.
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Affiliation(s)
- Maria Lucia Sampaio Guther
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Alan R. Prescott
- Dundee Imaging Facility, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Sabine Kuettel
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michele Tinti
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Michael A. J. Ferguson
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee, United Kingdom
- * E-mail:
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Catazaro J, Caprez A, Swanson D, Powers R. Functional Evolution of Proteins. Proteins 2019; 87:492-501. [PMID: 30714210 DOI: 10.1002/prot.25670] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 11/02/2018] [Accepted: 01/31/2019] [Indexed: 11/12/2022]
Abstract
The functional evolution of proteins advances through gene duplication followed by functional drift, whereas molecular evolution occurs through random mutational events. Over time, protein active-site structures or functional epitopes remain highly conserved, which enables relationships to be inferred between distant orthologs or paralogs. In this study, we present the first functional clustering and evolutionary analysis of the RCSB Protein Data Bank (RCSB PDB) based on similarities between active-site structures. All of the ligand-bound proteins within the RCSB PDB were scored using our Comparison of Protein Active-site Structures (CPASS) software and database (http://cpass.unl.edu/). Principal component analysis was then used to identify 4431 representative structures to construct a phylogenetic tree based on the CPASS comparative scores (http://itol.embl.de/shared/jcatazaro). The resulting phylogenetic tree identified a sequential, step-wise evolution of protein active-sites and provides novel insights into the emergence of protein function or changes in substrate specificity based on subtle changes in geometry and amino acid composition.
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Affiliation(s)
- Jonathan Catazaro
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Adam Caprez
- Holland Computing Center, Office of Research, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - David Swanson
- Holland Computing Center, Department of Computer Science and Engineering, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska.,Department of Chemistry, Nebraska Center for Integrated Biomolecular Communication, Lincoln, Nebraska
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Eltahan R, Guo F, Zhang H, Xiang L, Zhu G. Discovery of ebselen as an inhibitor of Cryptosporidium parvum glucose-6-phosphate isomerase (CpGPI) by high-throughput screening of existing drugs. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:43-49. [PMID: 29414105 PMCID: PMC6114080 DOI: 10.1016/j.ijpddr.2018.01.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Revised: 01/14/2018] [Accepted: 01/17/2018] [Indexed: 12/30/2022]
Abstract
Cryptosporidium parvum is a water-borne and food-borne apicomplexan pathogen. It is one of the top four diarrheal-causing pathogens in children under the age of five in developing countries, and an opportunistic pathogen in immunocompromised individuals. Unlike other apicomplexans, C. parvum lacks Kreb's cycle and cytochrome-based respiration, thus relying mainly on glycolysis to produce ATP. In this study, we characterized the primary biochemical features of the C. parvum glucose-6-phosphate isomerase (CpGPI) and determined its Michaelis constant towards fructose-6-phosphate (Km = 0.309 mM, Vmax = 31.72 nmol/μg/min). We also discovered that ebselen, an organoselenium drug, was a selective inhibitor of CpGPI by high-throughput screening of 1200 known drugs. Ebselen acted on CpGPI as an allosteric noncompetitive inhibitor (IC50 = 8.33 μM; Ki = 36.33 μM), while complete inhibition of CpGPI activity was not achieved. Ebselen could also inhibit the growth of C. parvum in vitro (EC50 = 165 μM) at concentrations nontoxic to host cells, albeit with a relatively small in vitro safety window of 4.2 (cytotoxicity TC50 on HCT-8 cells = 700 μM). Additionally, ebselen might also target other enzymes in the parasite, leading to the parasite growth reduction. Therefore, although ebselen is useful in studying the inhibition of CpGPI enzyme activity, further proof is needed to chemically and/or genetically validate CpGPI as a drug target. Cryptosporidium parvum possesses a single glucose-6-phosphate isomerase (CpGPI). CpGPI displays Michaelis-Menten kinetics towards fructose-6P (Km = 0.309 mM). The organoselenium ebselen is a CpGPI inhibitor identified from 1200 existing drugs. Ebselen displays allosteric noncompetitive inhibition on CpGPI (Ki = 36.33 μM). Ebeselen could inhibit the growth of C. parvum in vitro (EC50 = 165 μM).
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Affiliation(s)
- Rana Eltahan
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4467, USA
| | - Fengguang Guo
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4467, USA
| | - Haili Zhang
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4467, USA
| | - Lixin Xiang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | - Guan Zhu
- Department of Veterinary Pathobiology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, 77843-4467, USA.
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Ogungbe IV, Setzer WN. The Potential of Secondary Metabolites from Plants as Drugs or Leads against Protozoan Neglected Diseases-Part III: In-Silico Molecular Docking Investigations. Molecules 2016; 21:E1389. [PMID: 27775577 PMCID: PMC6274513 DOI: 10.3390/molecules21101389] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 10/06/2016] [Accepted: 10/12/2016] [Indexed: 12/11/2022] Open
Abstract
Malaria, leishmaniasis, Chagas disease, and human African trypanosomiasis continue to cause considerable suffering and death in developing countries. Current treatment options for these parasitic protozoal diseases generally have severe side effects, may be ineffective or unavailable, and resistance is emerging. There is a constant need to discover new chemotherapeutic agents for these parasitic infections, and natural products continue to serve as a potential source. This review presents molecular docking studies of potential phytochemicals that target key protein targets in Leishmania spp., Trypanosoma spp., and Plasmodium spp.
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Affiliation(s)
- Ifedayo Victor Ogungbe
- Department of Chemistry and Biochemistry, Jackson State University, Jackson, MS 39217, USA.
| | - William N Setzer
- Department of Chemistry, University of Alabama in Huntsville, Huntsville, AL 35899, USA.
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Smirlis D, Soares MBP. Selection of molecular targets for drug development against trypanosomatids. Subcell Biochem 2014; 74:43-76. [PMID: 24264240 DOI: 10.1007/978-94-007-7305-9_2] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Trypanosomatid parasites are a group of flagellated protozoa that includes the genera Leishmania and Trypanosoma, which are the causative agents of diseases (leishmaniases, sleeping sickness and Chagas disease) that cause considerable morbidity and mortality, affecting more than 27 million people worldwide. Today no effective vaccines for the prevention of these diseases exist, whereas current chemotherapy is ineffective, mainly due to toxic side effects of current drugs and to the emergence of drug resistance and lack of cost effectiveness. For these reasons, rational drug design and the search of good candidate drug targets is of prime importance. The search for drug targets requires a multidisciplinary approach. To this end, the completion of the genome project of many trypanosomatid species gives a vast amount of new information that can be exploited for the identification of good drug candidates with a prediction of "druggability" and divergence from mammalian host proteins. In addition, an important aspect in the search for good drug targets is the "target identification" and evaluation in a biological pathway, as well as the essentiality of the gene in the mammalian stage of the parasite, which is provided by basic research and genetic and proteomic approaches. In this chapter we will discuss how these bioinformatic tools and experimental evaluations can be integrated for the selection of candidate drug targets, and give examples of metabolic and signaling pathways in the parasitic protozoa that can be exploited for rational drug design.
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In-silico Leishmania target selectivity of antiparasitic terpenoids. Molecules 2013; 18:7761-847. [PMID: 23823876 PMCID: PMC6270436 DOI: 10.3390/molecules18077761] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 06/23/2013] [Accepted: 06/26/2013] [Indexed: 01/21/2023] Open
Abstract
Neglected Tropical Diseases (NTDs), like leishmaniasis, are major causes of mortality in resource-limited countries. The mortality associated with these diseases is largely due to fragile healthcare systems, lack of access to medicines, and resistance by the parasites to the few available drugs. Many antiparasitic plant-derived isoprenoids have been reported, and many of them have good in vitro activity against various forms of Leishmania spp. In this work, potential Leishmania biochemical targets of antiparasitic isoprenoids were studied in silico. Antiparasitic monoterpenoids selectively docked to L. infantum nicotinamidase, L. major uridine diphosphate-glucose pyrophosphorylase and methionyl t-RNA synthetase. The two protein targets selectively targeted by germacranolide sesquiterpenoids were L. major methionyl t-RNA synthetase and dihydroorotate dehydrogenase. Diterpenoids generally favored docking to L. mexicana glycerol-3-phosphate dehydrogenase. Limonoids also showed some selectivity for L. mexicana glycerol-3-phosphate dehydrogenase and L. major dihydroorotate dehydrogenase while withanolides docked more selectively with L. major uridine diphosphate-glucose pyrophosphorylase. The selectivity of the different classes of antiparasitic compounds for the protein targets considered in this work can be explored in fragment- and/or structure-based drug design towards the development of leads for new antileishmanial drugs.
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Jacobs RT, Nare B, Phillips MA. State of the art in African trypanosome drug discovery. Curr Top Med Chem 2011; 11:1255-74. [PMID: 21401507 PMCID: PMC3101707 DOI: 10.2174/156802611795429167] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2010] [Accepted: 11/25/2010] [Indexed: 11/22/2022]
Abstract
African sleeping sickness is endemic in sub-Saharan Africa where the WHO estimates that 60 million people are at risk for the disease. Human African trypanosomiasis (HAT) is 100% fatal if untreated and the current drug therapies have significant limitations due to toxicity and difficult treatment regimes. No new chemical agents have been approved since eflornithine in 1990. The pentamidine analog DB289, which was in late stage clinical trials for the treatment of early stage HAT recently failed due to toxicity issues. A new protocol for the treatment of late-stage T. brucei gambiense that uses combination nifurtomox/eflornithine (NECT) was recently shown to have better safety and efficacy than eflornithine alone, while being easier to administer. This breakthrough represents the only new therapy for HAT since the approval of eflornithine. A number of research programs are on going to exploit the unusual biochemical pathways in the parasite to identify new targets for target based drug discovery programs. HTS efforts are also underway to discover new chemical entities through whole organism screening approaches. A number of inhibitors with anti-trypanosomal activity have been identified by both approaches, but none of the programs are yet at the stage of identifying a preclinical candidate. This dire situation underscores the need for continued effort to identify new chemical agents for the treatment of HAT.
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Affiliation(s)
- Robert T. Jacobs
- SCYNEXIS, Inc., Research Triangle Park, North Carolina 27709-2878
| | - Bakela Nare
- SCYNEXIS, Inc., Research Triangle Park, North Carolina 27709-2878
| | - Margaret A. Phillips
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, 6001 Forest Park Rd, Dallas, Texas 75390-9041
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Aoki KI, Tanaka N, Kusakabe Y, Fukumi C, Haga A, Nakanishi M, Kitade Y, Nakamura KT. Crystallization and preliminary X-ray crystallographic study of phosphoglucose isomerase from Plasmodium falciparum. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:333-6. [PMID: 20208175 PMCID: PMC2833051 DOI: 10.1107/s1744309110001740] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Accepted: 01/14/2010] [Indexed: 11/10/2022]
Abstract
Phosphoglucose isomerase (PGI) is a key enzyme in glycolysis and glycogenesis that catalyses the interconversion of glucose 6-phosphate (G6P) and fructose 6-phosphate (F6P). For crystallographic studies, PGI from the human malaria parasite Plasmodium falciparum (PfPGI) was overproduced in Escherichia coli, purified and crystallized using the hanging-drop vapour-diffusion method. X-ray diffraction data to 1.5 A resolution were collected from an orthorhombic crystal form belonging to space group P2(1)2(1)2(1) with unit-cell parameters a = 103.3, b = 104.1, c = 114.6 A. Structural analysis by molecular replacement is in progress.
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Affiliation(s)
- Ken-ichi Aoki
- School of Pharmacy, Showa University, Tokyo 142-8555, Japan
| | | | | | - Chiharu Fukumi
- School of Pharmacy, Showa University, Tokyo 142-8555, Japan
| | - Arayo Haga
- Gifu Prefectural Research Institute for Health and Environmental Science, Kakamigahara 504-0838, Japan
- Gifu Pharmaceutical University, Gifu 502-8585, Japan
| | - Masayuki Nakanishi
- College of Pharmaceutical Sciences, Matsuyama University, Ehime 790-8578, Japan
| | - Yukio Kitade
- Faculty of Engineering, Gifu University, Gifu 501-1193, Japan
- Center for Advanced Drug Research, Gifu University, Gifu 501-1193, Japan
- Center for Emerging Infectious Diseases, Gifu University, Gifu 501-1193, Japan
- Graduate School of Drug Discovery and Medical Information Sciences, Gifu University, Gifu 501-1193, Japan
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