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Ahmed FS, Helmy WS, Alfuhaid NA, Moustafa MAM. Target Enzymes of Origanum majorana and Rosmarinus officinalis Essential Oils in Black Cutworm ( Agrotis ipsilon): In Vitro and In Silico Studies. INSECTS 2024; 15:483. [PMID: 39057216 PMCID: PMC11276864 DOI: 10.3390/insects15070483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2024] [Revised: 06/15/2024] [Accepted: 06/22/2024] [Indexed: 07/28/2024]
Abstract
In this study, in vitro and in silico approaches were employed to assess the toxicity of marjoram (Origanum majorana) and rosemary (Rosmarinus officinalis) essential oils (EOs) to A. ipsilon larvae. The study determined the activities of ATPases in the larvae after treatment with the LC20 and LC70 of each EO. α-esterase and glutathione-S-transferase (GST) activities were also determined after treatment with LC10 and LC30 of each EO. Furthermore, molecular docking was employed to determine the binding affinity of terpinene-4-ol and α-pinene, the major constituents of O. majorana, and R. officinalis EOs, respectively, compared to the co-crystallized ligand of α-esterase, diethyl hydrogen phosphate (DPF). Toxicity assays revealed that O. majorana EO was more toxic than R. officinalis EO to the A. ipsilon larvae at 96 h post-treatment. However, the LC20 and LC70 of the latter significantly inhibited the activity of the Na+-K+ pump at almost all intervals. The same concentrations significantly inhibited the Mg2+/Ca2+-ATPase and Ca2+ pump at 96 h post-treatment. In contrast, O. majorana EO showed a variable effect on the Na+-K+ pump across different time intervals. On the other hand, LC10 and LC30 of both EOs showed varied effects on α-esterase and GST over time. Molecular docking revealed energy scores of -4.51 and -4.29 kcal/mol for terpinene-4-ol and α-pinene, respectively, compared to a score of -4.67 for PDF. Our study demonstrated the toxicity of the tested EOs to A. ipsilon, suggesting their potential efficacy as insecticides.
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Affiliation(s)
- Fatma S. Ahmed
- Department of Economic Entomology and Pesticides, Faculty of Agriculture, Cairo University, Giza 12613, Egypt; (F.S.A.); (W.S.H.)
| | - Walid S. Helmy
- Department of Economic Entomology and Pesticides, Faculty of Agriculture, Cairo University, Giza 12613, Egypt; (F.S.A.); (W.S.H.)
| | - Nawal Abdulaziz Alfuhaid
- Department of Biology, College of Science and Humanities, Prince Sattam Bin Abdulaziz University, Al-Kharj 11942, Saudi Arabia;
| | - Moataz A. M. Moustafa
- Department of Economic Entomology and Pesticides, Faculty of Agriculture, Cairo University, Giza 12613, Egypt; (F.S.A.); (W.S.H.)
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Shinn EJ, Tajkhorshid E. Generating Concentration Gradients across Membranes for Molecular Dynamics Simulations of Periodic Systems. Int J Mol Sci 2024; 25:3616. [PMID: 38612428 PMCID: PMC11012027 DOI: 10.3390/ijms25073616] [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: 02/20/2024] [Revised: 03/15/2024] [Accepted: 03/20/2024] [Indexed: 04/14/2024] Open
Abstract
The plasma membrane forms the boundary between a living entity and its environment and acts as a barrier to permeation and flow of substances. Several computational means of calculating permeability have been implemented for molecular dynamics (MD) simulations-based approaches. Except for double bilayer systems, most permeability studies have been performed under equilibrium conditions, in large part due to the challenges associated with creating concentration gradients in simulations utilizing periodic boundary conditions. To enhance the scientific understanding of permeation and complement the existing computational means of characterizing membrane permeability, we developed a non-equilibrium method that enables the generation and maintenance of steady-state gradients in MD simulations. We utilize PBCs advantageously by imposing a directional bias to the motion of permeants so that their crossing of the boundary replenishes the gradient, like a previous study on ions. Under these conditions, a net flow of permeants across membranes may be observed to determine bulk permeability by a direct application of J=PΔc. In the present study, we explore the results of its application to an exemplary O2 and POPC bilayer system, demonstrating accurate and precise permeability measurements. In addition, we illustrate the impact of permeant concentration and the choice of thermostat on the permeability. Moreover, we demonstrate that energetics of permeation can be closely examined by the dissipation of the gradient across the membrane to gain nuanced insights into the thermodynamics of permeability.
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Affiliation(s)
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Resource Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
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Lim JJ, Suh Y, Faustman EM, Cui JY. Perfluorinated Carboxylic Acids with Increasing Carbon Chain Lengths Upregulate Amino Acid Transporters and Modulate Compensatory Response of Xenobiotic Transporters in HepaRG Cells. Drug Metab Dispos 2022; 50:1396-1413. [PMID: 34857530 PMCID: PMC9513853 DOI: 10.1124/dmd.121.000477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 11/23/2021] [Indexed: 12/16/2022] Open
Abstract
Perfluorinated carboxylic acids (PFCAs) are widespread environmental pollutants for which human exposure has been documented. PFCAs at high doses are known to regulate xenobiotic transporters partly through peroxisome proliferator-activated receptor alpha (PPARα) and constitutive androstane receptor (CAR) in rodent models. Less is known regarding how various PFCAs at a lower concentration modulate transporters for endogenous substrates, such as amino acids in human hepatocytes. Such studies are of particular importance because amino acids are involved in chemical detoxification, and their transport system may serve as a promising therapeutic target for structurally similar xenobiotics. The focus of this study was to further elucidate how PFCAs modulate transporters involved in intermediary metabolism and xenobiotic biotransformation. We tested the hepatic transcriptomic response of HepaRG cells exposed to 45 μM of perfluorooctanoic acid, perfluorononanoic acid, or perfluorodecanoic acid in triplicates for 24 hours (vehicle: 0.1% DMSO), as well as the prototypical ligands for PPARα (WY-14643, 45 μM) and CAR (6-(4-chlorophenyl)imidazo[2,1-b][1,3]thiazole-5-carbaldehyde O-(3,4-dichlorobenzyl)oxime [CITCO], 2 μM). PFCAs with increasing carbon chain lengths (C8-C10) regulated more liver genes, with amino acid metabolism and transport ranked among the top enriched pathways and PFDA ranked as the most potent PFCA tested. Genes encoding amino acid transporters, which are essential for protein synthesis, were novel inducible targets by all three PFCAs, suggesting a potentially protective mechanism to reduce further toxic insults. None of the transporter regulations appeared to be through PPARα or CAR but potential involvement of nuclear factor erythroid 2-related factor 2 is noted for all 3 PFCAs. In conclusion, PFCAs with increasing carbon chain lengths up-regulate amino acid transporters and modulate xenobiotic transporters to limit further toxic exposures in HepaRG cells. SIGNIFICANCE STATEMENT: Little is known regarding how various perfluorinated carboxylic acids modulate the transporters for endogenous substrates in human liver cells. Using HepaRG cells, this study is among the first to show that perfluorinated carboxylic acids with increasing carbon chain lengths upregulate amino acid transporters, which are essential for protein synthesis, and modulate xenobiotic transporters to limit further toxic exposures at concentrations lower than what was used in the literature.
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Affiliation(s)
- Joe Jongpyo Lim
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Youjun Suh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Elaine M Faustman
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Julia Yue Cui
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
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Zhang X, Akcan E, Correia M, Rameika N, Kundu S, Stoimenov I, Rendo V, Eriksson AU, Haraldsson M, Globisch D, Sjöblom T. Enhanced cytotoxicity of a novel family of ATPase inhibitors in colorectal cancer cells with high NAT2 activity. Biochem Pharmacol 2022; 203:115184. [PMID: 35872325 DOI: 10.1016/j.bcp.2022.115184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/15/2022] [Accepted: 07/18/2022] [Indexed: 11/30/2022]
Abstract
Loss of heterozygosity (LOH) is a hallmark feature of cancer genomes that reduces allelic variation, thereby creating tumor specific vulnerabilities which could be exploited for therapeutic purposes. We previously reported that loss of drug metabolic arylamine N-acetyltransferase 2 (NAT2) activity following LOH at 8p22 could be targeted for collateral lethality anticancer therapy in colorectal cancer (CRC). Here, we report a novel compound CBK034026C that exhibits specific toxicity towards CRC cells with high NAT2 activity. Connectivity Map analysis revealed that CBK034026C elicited a response pattern related to ATPase inhibitors. Similar to ouabain, a potent inhibitor of the Na+/K+-ATPase, CBK034026C activated the Nf-kB pathway. Further metabolomic profiling revealed downregulation of pathways associated with antioxidant defense and mitochondrial metabolism in CRC cells with high NAT2 activity, thereby weakening the protective response to oxidative stress induced by CBK034026C. The identification of a small molecule targeting metabolic vulnerabilities caused by NAT2 activity provides novel avenues for development of anticancer agents.
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Affiliation(s)
- Xiaonan Zhang
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Ece Akcan
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Mario Correia
- Department of Chemistry, BMC, Science for Life Laboratory, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Natallia Rameika
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Snehangshu Kundu
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Ivaylo Stoimenov
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Veronica Rendo
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden; Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA, 02215, USA
| | - Anna U Eriksson
- Department of Chemistry, CBCS, KBC-C4, Umeå University, SE-901 87 UMEÅ, Sweden
| | - Martin Haraldsson
- Chemical Biology Consortium Sweden (CBCS), Science for Life Laboratory, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Daniel Globisch
- Department of Chemistry, BMC, Science for Life Laboratory, Uppsala University, SE-751 24 Uppsala, Sweden
| | - Tobias Sjöblom
- Department of Immunology, Genetics and Pathology, Uppsala University, SE-751 85 Uppsala, Sweden.
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Abalenikhina YV, Erokhina PD, Mylnikov PY, Shchulkin AV, Yakusheva EN. Functioning of the P-glycoprotein Membrane Transport Protein under Conditions of the Inhibition of Glutathione Synthesis. APPL BIOCHEM MICRO+ 2022. [DOI: 10.1134/s0003683822030024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Pizzagalli MD, Bensimon A, Superti‐Furga G. A guide to plasma membrane solute carrier proteins. FEBS J 2021; 288:2784-2835. [PMID: 32810346 PMCID: PMC8246967 DOI: 10.1111/febs.15531] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 08/07/2020] [Accepted: 08/17/2020] [Indexed: 12/13/2022]
Abstract
This review aims to serve as an introduction to the solute carrier proteins (SLC) superfamily of transporter proteins and their roles in human cells. The SLC superfamily currently includes 458 transport proteins in 65 families that carry a wide variety of substances across cellular membranes. While members of this superfamily are found throughout cellular organelles, this review focuses on transporters expressed at the plasma membrane. At the cell surface, SLC proteins may be viewed as gatekeepers of the cellular milieu, dynamically responding to different metabolic states. With altered metabolism being one of the hallmarks of cancer, we also briefly review the roles that surface SLC proteins play in the development and progression of cancer through their influence on regulating metabolism and environmental conditions.
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Affiliation(s)
- Mattia D. Pizzagalli
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Ariel Bensimon
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
| | - Giulio Superti‐Furga
- CeMM, Research Center for Molecular Medicine of the Austrian Academy of SciencesViennaAustria
- Center for Physiology and PharmacologyMedical University of ViennaAustria
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Baldo AP, Tardiff JC, Schwartz SD. Mechanochemical Function of Myosin II: Investigation into the Recovery Stroke and ATP Hydrolysis. J Phys Chem B 2020; 124:10014-10023. [PMID: 33136401 PMCID: PMC7696650 DOI: 10.1021/acs.jpcb.0c05762] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Myosin regulates muscle function through a complex cycle of conformational rearrangements coupled with the hydrolysis of adenosine triphosphate (ATP). The recovery stroke reorganizes the myosin active site to hydrolyze ATP and cross bridge with the thin filament to produce muscle contraction. Engineered mutations K84M and R704E in Dictyostelium myosin have been designed to specifically inhibit the recovery stroke and have been shown to indirectly affect the ATPase activity of myosin. We investigated these mutagenic perturbations to the recovery stroke and generated thermodynamically correct and unbiased trajectories for native ATP hydrolysis with computationally enhanced sampling methods. Our methodology was able to resolve experimentally observed changes to kinetic and equilibrium dynamics for the recovery stroke with the correct prediction in the severity of these changes. For ATP hydrolysis, the sequential nature along with the stabilization of a metaphosphate intermediate was observed in agreement with previous studies. However, we observed glutamate 459 being utilized as a proton abstractor to prime the attacking water instead of a lytic water, a phenomenon not well categorized in myosin but has in other ATPases. Both rare event methodologies can be extended to human myosin to investigate isoformic differences from Dictyostelium and scan cardiomyopathic mutations to see differential perturbations to kinetics of other conformational changes in myosin such as the power stroke.
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Affiliation(s)
- Anthony P Baldo
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
| | - Jil C Tardiff
- Department of Biomedical Engineering, University of Arizona, Tucson, Arizona 85724, United States
| | - Steven D Schwartz
- Department of Chemistry and Biochemistry, University of Arizona, Tucson, Arizona 85721, United States
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Menzikov S. Biochemical properties of the sensitivity to GABA Aergic ligands, Cl -/HCO 3--ATPase isolated from fish (Cyprinus carpio) olfactory mucosa and brain. FISH PHYSIOLOGY AND BIOCHEMISTRY 2018; 44:583-597. [PMID: 29218440 DOI: 10.1007/s10695-017-0455-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
This paper presents a comparative study of the roles of Cl- and HCO3- in the functioning of the GABAAR-associated Cl-/HCO3--ATPase of the plasma membranes of the olfactory sensory neurons (OSNs) and mature brain neurons (MBNs) of fish. The ATPase activity of OSNs and its dephosphorylation were increased twofold by Cl-(15-30 mmol l-1), whereas the enzyme from MBNs was not significantly affected by Cl-. By contrast, HCO3-(15-30 mmol l-1) significantly activated the MBN enzyme and its dephosphorylation, but had no effect on the OSN ATPase. The maximum ATPase activity and protein dephosphorylation was observed in the presence of both Cl-(15 mmol l-1)/HCO3-(27 mmol l-1) and these activities were inhibited in the presence of picrotoxin (100 μmol l-1), bumetanide (150 μmol l-1), and DIDS (1000 μmol l-1). SDS-PAGE revealed that ATPases purified from the neuronal membrane have a subunit with molecular mass of ~ 56 kDa that binds [3H]muscimol and [3H]flunitrazepam. Direct phosphorylation of the enzymes in the presence of ATP-γ-32P and Mg2+, as well as Cl-/HCO3- sensitive dephosphorylation, is also associated with this 56 kDa peptide. Both preparations also showed one subunit with molecular mass 56 kDa that was immunoreactive with GABAAR β3 subunit. The use of a fluorescent dye for Cl- demonstrated that HCO3-(27 mmol l-1) causes a twofold increase in Cl- influx into proteoliposomes containing reconstituted ATPases from MBNs, but HCO3- had no effect on the reconstituted enzyme from OSNs. These data are the first to demonstrate a differential effect of Cl- and HCO3- in the regulation of the Cl-/HCO3--ATPases functioning in neurons with different specializations.
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Affiliation(s)
- Sergey Menzikov
- Department Russian Academy of Science, Institute of General Pathology and Pathophysiology, 8, Baltiyskaya st., Moscow, Russia, 125315.
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The oppD Gene and Putative Peptidase Genes May Be Required for Virulence in Mycoplasma gallisepticum. Infect Immun 2017; 85:IAI.00023-17. [PMID: 28348054 DOI: 10.1128/iai.00023-17] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/19/2017] [Indexed: 11/20/2022] Open
Abstract
Relatively few virulence genes have been identified in pathogenic mycoplasmas, so we used signature-tagged mutagenesis to identify mutants of the avian pathogen Mycoplasma gallisepticum with a reduced capacity to persist in vivo and compared the levels of virulence of selected mutants in experimentally infected chickens. Four mutants had insertions in one of the two incomplete oppABCDF operons, and a further three had insertions in distinct hypothetical genes, two containing peptidase motifs and one containing a member of a gene family. The three hypothetical gene mutants and the two with insertions in oppD1 were used to infect chickens, and all five were shown to have a reduced capacity to induce respiratory tract lesions. One oppD1 mutant and the MGA_1102 and MGA_1079 mutants had a greatly reduced capacity to persist in the respiratory tract and to induce systemic antibody responses against M. gallisepticum The other oppD1 mutant and the MGA_0588 mutant had less capacity than the wild type to persist in the respiratory tract but did elicit systemic antibody responses. Although M. gallisepticum carries two incomplete opp operons, one of which has been acquired by horizontal gene transfer, our results suggest that one of the copies of oppD may be required for full expression of virulence. We have also shown that three hypothetical genes, two of which encode putative peptidases, may be required for full expression of virulence in M. gallisepticum. None of these genes has previously been shown to influence virulence in pathogenic mycoplasmas.
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Menzikov SA, Karpova MN, Kuznetsova LV, Klishina NY. GABA<sub>A</sub>-Coupled Cl-/ HCO<sub>3</sub><sup style="margin-left:-10px">-</sup>-ATPase from Plasma Membrane of the Rat Brain: Role of HCO<sub>3</sub><sup style="margin-left:-10px">-</sup> in the Enzyme Activation. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/aer.2015.31002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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11
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Neibergs HL, Seabury CM, Wojtowicz AJ, Wang Z, Scraggs E, Kiser JN, Neupane M, Womack JE, Van Eenennaam A, Hagevoort GR, Lehenbauer TW, Aly S, Davis J, Taylor JF. Susceptibility loci revealed for bovine respiratory disease complex in pre-weaned holstein calves. BMC Genomics 2014; 15:1164. [PMID: 25534905 PMCID: PMC4445561 DOI: 10.1186/1471-2164-15-1164] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 12/11/2014] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Bovine respiratory disease complex (BRDC) is an infectious disease of cattle that is caused by a combination of viral and/or bacterial pathogens. Selection for cattle with reduced susceptibility to respiratory disease would provide a permanent tool for reducing the prevalence of BRDC. The objective of this study was to identify BRDC susceptibility loci in pre-weaned Holstein calves as a prerequisite to using genetic improvement as a tool for decreasing the prevalence of BRDC. High density SNP genotyping with the Illumina BovineHD BeadChip was conducted on 1257 male and 757 female Holstein calves from California (CA), and 767 calves identified as female from New Mexico (NM). Of these, 1382 were classified as BRDC cases, and 1396 were classified as controls, with all phenotypes assigned using the McGuirk health scoring system. During the acquisition of blood for DNA isolation, two deep pharyngeal and one mid-nasal diagnostic swab were obtained from each calf for the identification of bacterial and viral pathogens. Genome-wide association analyses were conducted using four analytical approaches (EIGENSTRAT, EMMAX-GRM, GBLUP and FvR). The most strongly associated SNPs from each individual analysis were ranked and evaluated for concordance. The heritability of susceptibility to BRDC in pre-weaned Holstein calves was estimated. RESULTS The four statistical approaches produced highly concordant results for 373 top ranked SNPs that defined 126 chromosomal regions for the CA population. Similarly, in NM, 370 SNPs defined 138 genomic regions that were identified by all four approaches. When the two populations were combined (i.e., CA + NM) and analyzed, 324 SNPs defined 116 genomic regions that were associated with BRDC across all analytical methods. Heritability estimates for BRDC were 21% for both CA and NM as individual populations, but declined to 13% when the populations were combined. CONCLUSIONS Four analytical approaches utilizing both single and multi-marker association methods revealed common genomic regions associated with BRDC susceptibility that can be further characterized and used for genomic selection. Moderate heritability estimates were observed for BRDC susceptibility in pre-weaned Holstein calves, thereby supporting the application of genomic selection to reduce the prevalence of BRDC in U.S. Holsteins.
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Affiliation(s)
- Holly L Neibergs
- Department of Animal Sciences, Washington State University, P.O. Box 646310, Pullman, WA, 99164-6310, USA.
| | | | - Andrzej J Wojtowicz
- Department of Animal Sciences, Washington State University, P.O. Box 646310, Pullman, WA, 99164-6310, USA.
| | - Zeping Wang
- Department of Animal Sciences, Washington State University, P.O. Box 646310, Pullman, WA, 99164-6310, USA.
| | - Erik Scraggs
- Department of Animal Sciences, Washington State University, P.O. Box 646310, Pullman, WA, 99164-6310, USA.
| | - Jennifer N Kiser
- Department of Animal Sciences, Washington State University, P.O. Box 646310, Pullman, WA, 99164-6310, USA.
| | - Mahesh Neupane
- Department of Animal Sciences, Washington State University, P.O. Box 646310, Pullman, WA, 99164-6310, USA.
| | - James E Womack
- Department of Veterinary Pathobiology, Texas A&M University, College Station, USA.
| | | | - Gerald Robert Hagevoort
- Extension Animal Sciences and Natural Resources Department, New Mexico State University, Las Cruces, USA.
| | - Terry W Lehenbauer
- Department of Population Health and Reproduction, University of California Davis, Davis, USA.
| | - Sharif Aly
- Department of Population Health and Reproduction, University of California Davis, Davis, USA.
| | - Jessica Davis
- Department of Population Health and Reproduction, University of California Davis, Davis, USA.
| | - Jeremy F Taylor
- Division of Animal Sciences, University of Missouri, Columbia, USA.
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ATP synthase: the right size base model for nanomotors in nanomedicine. ScientificWorldJournal 2014; 2014:567398. [PMID: 24605056 PMCID: PMC3925597 DOI: 10.1155/2014/567398] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 12/05/2013] [Indexed: 11/17/2022] Open
Abstract
Nanomedicine results from nanotechnology where molecular scale minute precise nanomotors can be used to treat disease conditions. Many such biological nanomotors are found and operate in living systems which could be used for therapeutic purposes. The question is how to build nanomachines that are compatible with living systems and can safely operate inside the body? Here we propose that it is of paramount importance to have a workable base model for the development of nanomotors in nanomedicine usage. The base model must placate not only the basic requirements of size, number, and speed but also must have the provisions of molecular modulations. Universal occurrence and catalytic site molecular modulation capabilities are of vital importance for being a perfect base model. In this review we will provide a detailed discussion on ATP synthase as one of the most suitable base models in the development of nanomotors. We will also describe how the capabilities of molecular modulation can improve catalytic and motor function of the enzyme to generate a catalytically improved and controllable ATP synthase which in turn will help in building a superior nanomotor. For comparison, several other biological nanomotors will be described as well as their applications for nanotechnology.
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Tseng CW, Kanci A, Citti C, Rosengarten R, Chiu CJ, Chen ZH, Geary SJ, Browning GF, Markham PF. MalF is essential for persistence of Mycoplasma gallisepticum in vivo. MICROBIOLOGY-SGM 2013; 159:1459-1470. [PMID: 23657682 DOI: 10.1099/mic.0.067553-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
There is limited understanding of the molecular basis of virulence in the important avian pathogen Mycoplasma gallisepticum. To define genes that may be involved in colonization of chickens, a collection of mutants of the virulent Ap3AS strain of M. gallisepticum were generated by signature-tagged transposon mutagenesis. The collection included mutants with single insertions in the genes encoding the adhesin GapA and the cytadherence-related protein CrmA, and Western blotting confirmed that these mutants did not express these proteins. In two separate in vivo screenings, two GapA-deficient mutants (ST mutants 02-1 and 06-1) were occasionally recovered from birds, suggesting that GapA expression may not always be essential for persistence of strain Ap3AS. CrmA-deficient ST mutant 33-1 colonized birds poorly and had reduced virulence, indicating that CrmA was a significant virulence factor, but was not absolutely essential for colonization. ST mutant 04-1 contained a single transposon insertion in malF, a predicted ABC sugar transport permease, and could not be reisolated even when inoculated by itself into a group of birds, suggesting that expression of MalF was essential for persistence of M. galliseptium strain Ap3AS in infected birds.
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Affiliation(s)
- Chi-Wen Tseng
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anna Kanci
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Christine Citti
- Institute of Bacteriology, Mycology and Hygiene, University of Veterinary Medicine, Vienna, A-1210 Vienna, Austria.,INRA, ENVT, UMR 1225, 31076 Toulouse, France
| | - Renate Rosengarten
- Institute of Bacteriology, Mycology and Hygiene, University of Veterinary Medicine, Vienna, A-1210 Vienna, Austria
| | - Chien-Ju Chiu
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Zheng-Hong Chen
- Microbiology Department, Basic Medical College, Guiyang Medical University, Guiyang, Guizhou 550004, PR China
| | - Steven J Geary
- Center of Excellence for Vaccine Research, Department of Pathobiology and Veterinary Science, The University of Connecticut, Storrs, Connecticut 06269, USA
| | - Glenn F Browning
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Philip F Markham
- Asia-Pacific Centre for Animal Health, Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia
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Menzikov SA, Karpova MN, Kalinina MV. Effect of HCO3(-) ions on the ATP-dependent GABA(A) receptor-coupled Cl(-) channel in rat brain plasma membranes. Bull Exp Biol Med 2012; 152:38-42. [PMID: 22803035 DOI: 10.1007/s10517-011-1448-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
We studied the effect of Cl(-) (10-75 mM) and HCO(3)(-) ions (10-25 mM) on the ATP-dependent GABA(A) receptor-coupled Cl(-) channel (Cl(-)-ATPase) in rat brain plasma membranes. The total enzyme activity was detected in the presence of both anions at a Cl(-)/ HCO(3)(-) ratio of 5:1 (Cl(-), HCO(3)(-)-ATPase). Specific inhibitors of P-type transport ATPases (N-ethylmaleimide, o-vanadate, and oligomycin) suppressed Cl(-), HCO(3)(-)-ATPase, while the Cl(-)- and HCO(3)(-)-ATPase activities were low sensitive to these ligands. Bicuculline abolished the activating effect of Cl(-) and HCO(3)(-) ions on the enzyme. HCO(3)(-) ions had no effect on the ATP-dependent Cl(-) transport into proteoliposomes (with the involvement of reconstituted ATPase). In experiment with Cl(-)-preloaded liposomes, addition of HCO(3)(-) ions to the incubation medium caused the reversion of Cl(-) transport (ion efflux from liposomes). Our results suggest that HCO(3)(-) ions play an important role in the modification of properties of the ATP-dependent GABA(A) receptor-coupled Cl(-) channel and GABA(A) receptor-induced Cl(-)/ HCO(3)(-) exchange. These ions are probably involved in GABA(A) receptor-induced Cl(-)/ HCO(3)(-) exchange in neuronal membranes.
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Affiliation(s)
- S A Menzikov
- State Research Institute of General Pathology and Pathological Physiology, Russian Academy of Medical Sciences, Moscow, Russia.
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15
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Kondabagil K, Draper B, Rao VB. Adenine recognition is a key checkpoint in the energy release mechanism of phage T4 DNA packaging motor. J Mol Biol 2011; 415:329-42. [PMID: 22100308 DOI: 10.1016/j.jmb.2011.11.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Revised: 11/03/2011] [Accepted: 11/07/2011] [Indexed: 11/25/2022]
Abstract
ATP is the source of energy for numerous biochemical reactions in all organisms. Tailed bacteriophages use ATP to drive powerful packaging machines that translocate viral DNA into a procapsid and compact it to near-crystalline density. Here we report that a complex network of interactions dictates adenine recognition and ATP hydrolysis in the pentameric phage T4 large "terminase" (gp17) motor. The network includes residues that form hydrogen bonds at the edges of the adenine ring (Q138 and Q143), base-stacking interactions at the plane of the ring (I127 and R140), and cross-talking bonds between adenine, triphosphate, and Walker A P-loop (Y142, Q143, and R140). These interactions are conserved in other translocases such as type I/type III restriction enzymes and SF1/SF2 helicases. Perturbation of any of these interactions, even the loss of a single hydrogen bond, leads to multiple defects in motor functions. Adenine recognition is therefore a key checkpoint that ensures efficient ATP firing only when the fuel molecule is precisely engaged with the motor. This may be a common feature in the energy release mechanism of ATP-driven molecular machines that carry out numerous biomolecular reactions in biological systems.
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Affiliation(s)
- Kiran Kondabagil
- Department of Biology, The Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064, USA
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Harris NJ, Booth PJ. Folding and stability of membrane transport proteins in vitro. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1055-66. [PMID: 22100867 DOI: 10.1016/j.bbamem.2011.11.006] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 10/26/2011] [Accepted: 11/03/2011] [Indexed: 10/15/2022]
Abstract
Transmembrane transporters are responsible for maintaining a correct internal cellular environment. The inherent flexibility of transporters together with their hydrophobic environment means that they are challenging to study in vitro, but recently significant progress been made. This review will focus on in vitro stability and folding studies of transmembrane alpha helical transporters, including reversible folding systems and thermal denaturation. The successful re-assembly of a small number of ATP binding cassette transporters is also described as this is a significant step forward in terms of understanding the folding and assembly of these more complex, multi-subunit proteins. The studies on transporters discussed here represent substantial advances for membrane protein studies as well as for research into protein folding. The work demonstrates that large flexible hydrophobic proteins are within reach of in vitro folding studies, thus holding promise for furthering knowledge on the structure, function and biogenesis of ubiquitous membrane transporter families. This article is part of a Special Issue entitled: Protein Folding in Membranes.
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Li JQ, Chen M, Zou XP. PPIs reverse multidrug resistance to chemotherapy in gastric cancer by inhibiting vacuolar H +-ATPase signal pathway. Shijie Huaren Xiaohua Zazhi 2011; 19:3201-3206. [DOI: 10.11569/wcjd.v19.i31.3201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Multidrug resistance (MDR) in gastric cancer influences the effects of chemotherapy. The change in tumor microenvironment is intimately associated with multidrug resistance. Acidification and hypoxia are the two major characteristics of tumor microenvironment. The glucose metabolism in hypoxic conditions by the neoplasms leads to an intercellular pH drift towards acidity. But tumor cells can maintain intracellular to neutro-alkalinity. Vacuolar H+-ATPases may be involved in this process by regulating H+ excretion. Acidification of extracellular pH would trigger the intracellular PI3K/Akt signal pathway, activate mTOR, up-regulate the expression of HIF-1α, and promote the expression of P-gp and MRP1, resulting in multidrug resistance in gastric cancer. PPIs may change the tumor microenvironment by inhibiting the expression of vacuolar H+-ATPases, trigger the PI3K/Akt/mTOR/HIF-1α signal pathway and reverse multidrug resistance to chemotherapy in gastric cancer.
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18
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Abstract
Streptococcus pneumoniae is a major cause of pneumonia and meningitis. Airway colonization is a necessary precursor to disease, but little is known about how the bacteria establish and maintain colonization. Carbohydrates are required as a carbon source for pneumococcal growth and, therefore, for colonization. Free carbohydrates are not readily available in the naso-oropharynx; however, N- and O-linked glycans are common in the airway. Sialic acid is the most common terminal modification on N- and O-linked glycans and is likely encountered frequently by S. pneumoniae in the airway. Here we demonstrate that sialic acid supports pneumococcal growth when provided as a sole carbon source. Growth on sialic acid requires import into the bacterium. Three genetic regions have been proposed to encode pneumococcal sialic acid transporters: one sodium solute symporter and two ATP binding cassette (ABC) transporters. Data demonstrate that one of these, satABC, is required for transport of sialic acid. A satABC mutant displayed significantly reduced growth on both sialic acid and the human glycoprotein alpha-1. The importance of satABC for growth on human glycoprotein suggests that sialic acid transport may be important in vivo. Indeed, the satABC mutant was significantly reduced in colonization of the murine upper respiratory tract. This work demonstrates that S. pneumoniae is able to use sialic acid as a sole carbon source and that utilization of sialic acid is likely important during pneumococcal colonization.
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Zhu Z, Xue LM, Han T, Jiao L, Qin LP, Li YS, Zheng HC, Zhang QY. Antiosteoporotic effects and proteomic characterization of the target and mechanism of an Er-Xian Decoction on osteoblastic UMR-106 and osteoclasts induced from RAW264.7. Molecules 2010; 15:4695-710. [PMID: 20657386 PMCID: PMC6257636 DOI: 10.3390/molecules15074695] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Revised: 06/11/2010] [Accepted: 06/29/2010] [Indexed: 12/16/2022] Open
Abstract
Er-Xian Decoction (EXD) has been used for the treatment of osteoporosis disorders, menopausal syndrome, and other aging diseases in the Chinese traditional healthcare system. However, the targets and mechanism of action have not been clarified. This study was designed to investigate the effects and possible target proteins of EXD on osteoblastic UMR-106 cells and osteoclasts induced from RAW264.7 cells using the proteomic analysis technique. We found that EXD at a concentration of 50–200 μg/mL significantly enhanced osteoblastic UMR-106 cell proliferation, alkaline phosphatase (ALP) activity and formation of bone nodules, and decreased tartrate-resistant acid phosphatase (TRAP) activity and the bone resorption action of osteoclasts induced from RAW 264.7 cells. In EXD-treated osteoblasts, there were increases in the expression of heat-shock protein 1, high mobility group protein (Hmgb1), acidic ribosomal phosphoprotein P0, histone 2, carbonyl reductase 1, ATP synthase, aldolase A, and Rho GDP dissociation inhibitor (GDI)-alpha; and reduction in the expression of carbonic anhydrase 3, prohibitin, hemiferrin, far upstream element (FUSE)-binding protein. In EXD-treated osteoclasts, there were increases in the expression of vimentin, protein disulfide isomerase associated 3 and alpha-fetoprotein; and reduction in the expression of calnexin. These results indicated that EXD modulates bone metabolism through regulation of osteoblastic proliferation, apoptosis, and cell activation, and osteoclastic protein folding and aggregation.
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Affiliation(s)
- Zheng Zhu
- School of Pharmaceutical Sciences, China Medical University, No.92 Bei Er Road, He Ping District, Shenyang, 110001, China
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
- College of Traditional Chinese Material Medica, Shenyang Pharmaceutical University, Number 103 Wen Hua Road, Shen He District, Shenyang, 110016, China
- Authors to whom correspondence should be addressed; E-Mail: (Z.Z.); (Q.Y.Z.); Tel.: +86-21-81871303; Fax: +86-24-23256666-5271
| | - Li-Ming Xue
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
| | - Ting Han
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
| | - Lei Jiao
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
| | - Lu-Ping Qin
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
| | - Yu-Shan Li
- College of Traditional Chinese Material Medica, Shenyang Pharmaceutical University, Number 103 Wen Hua Road, Shen He District, Shenyang, 110016, China
| | - Han-Chen Zheng
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
| | - Qiao-Yan Zhang
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai, 200433, China
- Authors to whom correspondence should be addressed; E-Mail: (Z.Z.); (Q.Y.Z.); Tel.: +86-21-81871303; Fax: +86-24-23256666-5271
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Lomovskaya O, Zgurskaya HI, Bostian K. Bacterial Multidrug Transporters: Molecular and Clinical Aspects. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/9783527627424.ch5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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21
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Li W, Brudecki LE, Senior AE, Ahmad Z. Role of {alpha}-subunit VISIT-DG sequence residues Ser-347 and Gly-351 in the catalytic sites of Escherichia coli ATP synthase. J Biol Chem 2009; 284:10747-54. [PMID: 19240022 DOI: 10.1074/jbc.m809209200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
This paper describes the role of alpha-subunit VISIT-DG sequence residues alphaSer-347 and alphaGly-351 in catalytic sites of Escherichia coli F(1)F(o) ATP synthase. X-ray structures show the very highly conserved alpha-subunit VISIT-DG sequence in close proximity to the conserved phosphate-binding residues alphaArg-376, betaArg-182, betaLys-155, and betaArg-246 in the phosphate-binding subdomain. Mutations alphaS347Q and alphaG351Q caused loss of oxidative phosphorylation and reduced ATPase activity of F(1)F(o) in membranes by 100- and 150-fold, respectively, whereas alphaS347A mutation showed only a 13-fold loss of activity and also retained some oxidative phosphorylation activity. The ATPase of alphaS347Q mutant was not inhibited, and the alphaS347A mutant was slightly inhibited by MgADP-azide, MgADP-fluoroaluminate, or MgADP-fluoroscandium, in contrast to wild type and alphaG351Q mutant. Whereas 7-chloro-4-nitrobenzo-2-oxa-1, 3-diazole (NBD-Cl) inhibited wild type and alphaG351Q mutant ATPase essentially completely, ATPase in alphaS347A or alphaS347Q mutant was inhibited maximally by approximately 80-90%, although reaction still occurred at residue betaTyr-297, proximal to the alpha-subunit VISIT-DG sequence, near the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts inbetaE (empty) catalytic sites, as shown previously by x-ray structure analysis. Phosphate protected against NBD-Cl inhibition in wild type and alphaG351Q mutant but not in alphaS347Q or alphaS347A mutant. The results demonstrate that alphaSer-347 is an additional residue involved in phosphate-binding and transition state stabilization in ATP synthase catalytic sites. In contrast, alphaGly-351, although strongly conserved and clearly important for function, appears not to play a direct role.
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Affiliation(s)
- Wenzong Li
- Department of Biological Sciences, East Tennessee State University, Johnson City, Tennessee 37614, USA
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22
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Escherichia coli tat mutant strains are able to transport maltose in the absence of an active malE gene. Arch Microbiol 2008; 189:597-604. [PMID: 18385983 DOI: 10.1007/s00203-008-0356-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2007] [Revised: 01/23/2008] [Accepted: 02/13/2008] [Indexed: 10/22/2022]
Abstract
The twin-arginine transport (Tat) system is a prokaryotic protein transport system. Escherichia coli mutants in this pathway show a defect in cell separation during cell division, resulting in destabilization and permeability of the outer membrane. Maltose uptake is catalysed by a membrane-bound transporter of the ATP binding cassette (ABC) superfamily, where MalE is the essential periplasmic binding protein component. Here, we report that tat mutants are unexpectedly able to transport maltose in the absence of malE. This observation is specific to the MalE component since co-inactivation of malF, which encodes one of the channel components of the transporter, completely abolishes maltose transport even when the Tat system is inactivated. Genetic repair of the outer membrane leaky phenotype of the tat mutant strain re-established the absolute requirement for MalE in maltose uptake. In addition, we demonstrate that phenotypic repair of the outer membrane defect of the tat strain can also be achieved chemically by the inclusion of high concentrations of calcium or magnesium in the growth medium.
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Brudecki LE, Grindstaff JJ, Ahmad Z. Role of alphaPhe-291 residue in the phosphate-binding subdomain of catalytic sites of Escherichia coli ATP synthase. Arch Biochem Biophys 2008; 471:168-75. [PMID: 18242162 DOI: 10.1016/j.abb.2008.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2007] [Revised: 01/15/2008] [Accepted: 01/17/2008] [Indexed: 11/28/2022]
Abstract
The role of alphaPhe-291 residue in phosphate binding by Escherichia coli F1F0-ATP synthase was examined. X-ray structures of bovine mitochondrial enzyme suggest that this residue resides in close proximity to the conserved betaR246 residue. Herein, we show that mutations alphaF291D and alphaF291E in E. coli reduce the ATPase activity of F1F0 membranes by 350-fold. Yet, significant oxidative phosphorylation activity is retained. In contrast to wild-type, ATPase activities of mutants were not inhibited by MgADP-azide, MgADP-fluoroaluminate, or MgADP-fluoroscandium. Whereas, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) inhibited wild-type ATPase essentially completely, ATPase in mutants was inhibited maximally by approximately 75%, although reaction still occurred at residue betaTyr-297, proximal to alphaPhe-291 in the phosphate-binding pocket. Inhibition characteristics supported the conclusion that NBD-Cl reacts in betaE (empty) catalytic sites, as shown previously by X-ray structure analysis. Phosphate protected against NBD-Cl inhibition in wild-type but not in mutants. In addition, our data suggest that the interaction of alphaPhe-291 with phosphate during ATP hydrolysis or synthesis may be distinct.
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Affiliation(s)
- Laura E Brudecki
- Department of Biological Sciences, Box 70703, East Tennessee State University, Johnson City, TN 37614, USA
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24
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Transport ATPases into the year 2008: a brief overview related to types, structures, functions and roles in health and disease. J Bioenerg Biomembr 2008; 39:349-55. [DOI: 10.1007/s10863-007-9123-9] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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25
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Ishmukhametov RR, Pond JB, Al-Huqail A, Galkin MA, Vik SB. ATP synthesis without R210 of subunit a in the Escherichia coli ATP synthase. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2007; 1777:32-8. [PMID: 18068111 DOI: 10.1016/j.bbabio.2007.11.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 11/02/2007] [Accepted: 11/07/2007] [Indexed: 11/29/2022]
Abstract
Interactions between subunit a and oligomeric subunit c are essential for the coupling of proton translocation to rotary motion in the ATP synthase. A pair of previously described mutants, R210Q/Q252R and P204T/R210Q/Q252R [L.P. Hatch, G.B. Cox and S.M. Howitt, The essential arginine residue at position 210 in the a subunit of the Escherichia coli ATP synthase can be transferred to position 252 with partial retention of activity, J. Biol. Chem. 270 (1995) 29407-29412] has been constructed and further analyzed. These mutants, in which the essential arginine of subunit a, R210, was switched with a conserved glutamine residue, Q252, are shown here to be capable of both ATP synthesis by oxidative phosphorylation, and ATP-driven proton translocation. In addition, lysine can replace the arginine at position 252 with partial retention of both activities. The pH dependence of ATP-driven proton translocation was determined after purification of mutant enzymes, and reconstitution into liposomes. Proton translocation by the lysine mutant, and to a lesser extent the arginine mutant, dropped off sharply above pH 7.5, consistent with the requirement for a positive charge during function. Finally, the rates of ATP synthesis and of ATP-driven proton translocation were completely inhibited by treatment with DCCD (N,N'-dicyclohexylcarbodiimide), while rates of ATP hydrolysis by the mutants were not significantly affected, indicating that DCCD modification disrupts the F(1)-F(o) interface. The results suggest that minimal requirements for proton translocation by the ATP synthase include a positive charge in subunit a and a weak interface between subunit a and oligomeric subunit c.
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Affiliation(s)
- Robert R Ishmukhametov
- Department of Biological Sciences, Box 750376, Southern Methodist University, Dallas, TX 75275-0376, USA
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Abstract
Most organisms maintain a transmembrane sodium gradient for cell function. Despite the importance of Na(+) in physiology, no directly Na(+)-responsive signalling molecules are known. The CyaB1 and CyaB2 adenylyl cyclases of the cyanobacterium Anabaena PCC 7120 are inhibited by Na(+). A D360A mutation in the GAF-B domain of CyaB1 ablated cAMP-mediated autoregulation and Na(+) inhibition. Na(+) bound the isolated GAF domains of CyaB2. cAMP blocked Na(+) binding to GAF domains but Na(+) had no effect on cAMP binding. Na(+) altered GAF domain structure indicating a mechanism of inhibition independent of cAMP binding. DeltacyaB1 and DeltacyaB2 mutant strains did not grow below 0.6 mM Na(+) and DeltacyaB1 cells possessed defects in Na(+)/H(+) antiporter function. Replacement of the CyaB1 GAF domains with those of rat phosphodiesterase type 2 revealed that Na(+) inhibition has been conserved since the eukaryotic/bacterial divergence. CyaB1 and CyaB2 are the first identified directly Na(+)-responsive signalling molecules that function in sodium homeostasis and we propose a subset of GAF domains underpin an evolutionarily conserved Na(+) signalling mechanism.
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Affiliation(s)
- Martin Cann
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham, UK.
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Ponte-Sucre A. Availability and applications of ATP-binding cassette (ABC) transporter blockers. Appl Microbiol Biotechnol 2007; 76:279-86. [PMID: 17522856 DOI: 10.1007/s00253-007-1017-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2007] [Revised: 04/24/2007] [Accepted: 04/24/2007] [Indexed: 01/16/2023]
Abstract
ATP-binding cassette (ABC) transporters encompass membrane transport proteins that couple the energy derived from ATP hydrolysis to the translocation of solutes across biological membranes. The functions of these proteins include ancient and conserved mechanisms related to nutrition and pathogenesis in bacteria, spore formation in fungi, and signal transduction, protein secretion and antigen presentation in eukaryotes. Furthermore, one of the major causes of drug resistance and chemotherapeutic failure in both cancer and anti-infective therapies is the active movement of compounds across membranes carried out by ABC transporters. Thus, the clinical relevance of ABC transporters is enormous, and the membrane transporters related to chemoresistance are among the best-studied members of the ABC transporter superfamily. As ABC transporter blockers can be used in combination with current drugs to increase their efficacy, the (possible) impact of efflux pump inhibitors is of great clinical interest. The present review summarizes the progress made in recent years in the identification, design, availability, and applicability of ABC transporter blockers in experimental scenarios oriented towards improving the treatment of infectious diseases caused by microorganisms including parasites.
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Affiliation(s)
- Alicia Ponte-Sucre
- Laboratorio de Fisiología Molecular, Instituto de Medicina Experimental, Facultad de Medicina, Universidad Central de Venezuela, Caracas, Venezuela.
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Ausiello G, Peluso D, Via A, Helmer-Citterich M. Local comparison of protein structures highlights cases of convergent evolution in analogous functional sites. BMC Bioinformatics 2007; 8 Suppl 1:S24. [PMID: 17430569 PMCID: PMC1885854 DOI: 10.1186/1471-2105-8-s1-s24] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background We performed an exhaustive search for local structural similarities in an ensemble of non-redundant protein functional sites. With the purpose of finding new examples of convergent evolution, we selected only those matching sites composed of structural regions whose residue order is inverted in the relative protein sequences. Results A novel case of local analogy was detected between members of the ABC transporter and of the HprK/P families in their ATP binding site. This case cannot be derived by events of circular permutation since the residues of one of the region pairs are located in reverse order in the sequence of the two protein families. One of the analogous binding sites, the one identified in HprK/P, is known to also bind pyrophosphate, which is used as preferred energy source in its kinase and phosphorylase activity. Conclusion The discovery of this striking molecular similarity, also associated to a functional similarity, may help in suggesting new experiments aimed at a deeper understanding of members of the ABC transporter family known to be involved in many serious human diseases.
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Affiliation(s)
- Gabriele Ausiello
- Centre for Molecular Bioinformatics, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Daniele Peluso
- Centre for Molecular Bioinformatics, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Allegra Via
- Centre for Molecular Bioinformatics, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Manuela Helmer-Citterich
- Centre for Molecular Bioinformatics, Department of Biology, University of Rome "Tor Vergata", Rome, Italy
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Lin T, Islam O, Heese K. ABC transporters, neural stem cells and neurogenesis – a different perspective. Cell Res 2006; 16:857-71. [PMID: 17088897 DOI: 10.1038/sj.cr.7310107] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Stem cells intrigue. They have the ability to divide exponentially, recreate the stem cell compartment, as well as create differentiated cells to generate tissues. Therefore, they should be natural candidates to provide a renewable source of cells for transplantation applied in regenerative medicine. Stem cells have the capacity to generate specific tissues or even whole organs like the blood, heart, or bones. A subgroup of stem cells, the neural stem cells (NSCs), is characterized as a self-renewing population that generates neurons and glia of the developing brain. They can be isolated, genetically manipulated and differentiated in vitro and reintroduced into a developing, adult or a pathologically altered central nervous system. NSCs have been considered for use in cell replacement therapies in various neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. Characterization of genes with tightly controlled expression patterns during differentiation represents an approach to understanding the regulation of stem cell commitment. The regulation of stem cell biology by the ATP-binding cassette (ABC) transporters has emerged as an important new field of investigation. As a major focus of stem cell research is in the manipulation of cells to enable differentiation into a targeted cell population; in this review, we discuss recent literatures on ABC transporters and stem cells, and propose an integrated view on the role of the ABC transporters, especially ABCA2, ABCA3, ABCB1 and ABCG2, in NSCs' proliferation, differentiation and regulation, along with comparisons to that in hematopoietic and other stem cells.
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Affiliation(s)
- Tingting Lin
- Department of Molecular and Cell Biology, School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
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