1
|
Cai J, Geng Y, Zhang B, Li Y. Discovery of a Novel Integrative Conjugative Element ICE AplChn2 Related to SXT/R391 in Actinobacillus pleuropneumoniae. Microb Drug Resist 2024; 30:134-140. [PMID: 38181173 DOI: 10.1089/mdr.2023.0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2024] Open
Abstract
Objective: The objective of this study was to characterize ICEAplChn2, a novel SXT/R391-related integration and conjugation element (ICE) carrying 19 drug resistance genes, in a clinical isolate of Actinobacillus pleuropneumoniae from swine. Methods: Whole genome sequencing (WGS) of A. pleuropneumoniae CP063424 strain was completed using a combination of third-generation PacBio and second-generation Illumina. The putative ICE was predicted by the online tool ICEfinder. ICEAplChn2 was analyzed by PCR, conjugation experiments, and bioinformatics tools. Results: A. pleuropneumoniae CP063424 strain exhibited high minimum inhibitory concentrations of clindamycin (1,024 mg/L). The WGS data revealed that ICEAplChn2, with a length of 167,870 bp and encoding 151 genes, including multiple antibiotic resistance genes such as erm(42), VanE, LpxC, dfrA1, golS, aadA3, EreA, dfrA32, tetR(C), tet(C), sul2, aph(3)″-lb, aph(6)-l, floR, dfrA, ANT(3″)-IIa, catB11, and VanRE, was found to be related to the SXT/R391 family on the chromosome of A. pleuronipneumoniae CP063424. The circular intermediate of ICEAplChn2 was detected by PCR, but conjugation experiments showed that it was not self-transmissible. Conclusions: To our knowledge, ICEAplChn2 is the longest member with the most resistance genes in the SXT/R391 family. Meanwhile, ATP-binding cassette superfamily was found to be inserted in the ICEAplChn2 and possessed a new insertion region, which is the first description in the SXT/R391 family.
Collapse
Affiliation(s)
- Jinshuang Cai
- Key Laboratory of Bacteriology, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Yan Geng
- Key Laboratory of Bacteriology, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Baoge Zhang
- Key Laboratory of Bacteriology, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| | - Yufeng Li
- Key Laboratory of Bacteriology, College of Veterinary Medicine, Ministry of Agriculture, Nanjing Agricultural University, Nanjing, China
| |
Collapse
|
2
|
Novischi SYP, Karoly-Lakatos A, Chok K, Bonifer C, Becker-Baldus J, Glaubitz C. Probing the allosteric NBD-TMD crosstalk in the ABC transporter MsbA by solid-state NMR. Commun Biol 2024; 7:43. [PMID: 38182790 PMCID: PMC10770068 DOI: 10.1038/s42003-023-05617-0] [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: 06/11/2023] [Accepted: 11/21/2023] [Indexed: 01/07/2024] Open
Abstract
The ABC transporter MsbA plays a critical role in Gram-negative bacteria in the regulation of the outer membrane by translocating core-LPS across the inner membrane. Additionally, a broad substrate specificity for lipophilic drugs has been shown. The allosteric interplay between substrate binding in the transmembrane domains and ATP binding and turnover in the nucleotide-binding domains must be mediated via the NBD/TMD interface. Previous studies suggested the involvement of two intracellular loops called coupling helix 1 and 2 (CH1, CH2). Here, we demonstrate by solid-state NMR spectroscopy that substantial chemical shift changes within both CH1 and CH2 occur upon substrate binding, in the ATP hydrolysis transition state, and upon inhibitor binding. CH2 is domain-swapped within the MsbA structure, and it is noteworthy that substrate binding induces a larger response in CH2 compared to CH1. Our data demonstrate that CH1 and CH2 undergo structural changes as part of the TMD-NBD cross-talk.
Collapse
Affiliation(s)
- S Y Phoebe Novischi
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Andrea Karoly-Lakatos
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Kerby Chok
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Christian Bonifer
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Johanna Becker-Baldus
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 9, 60438, Frankfurt, Germany
| | - Clemens Glaubitz
- Institute for Biophysical Chemistry and Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max von Laue Str. 9, 60438, Frankfurt, Germany.
| |
Collapse
|
3
|
Yu L, Xu X, Chua WZ, Feng H, Ser Z, Shao K, Shi J, Wang Y, Li Z, Sobota RM, Sham LT, Luo M. Structural basis of peptide secretion for Quorum sensing by ComA. Nat Commun 2023; 14:7178. [PMID: 37935699 PMCID: PMC10630487 DOI: 10.1038/s41467-023-42852-9] [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: 04/12/2023] [Accepted: 10/23/2023] [Indexed: 11/09/2023] Open
Abstract
Quorum sensing (QS) is a crucial regulatory mechanism controlling bacterial signalling and holds promise for novel therapies against antimicrobial resistance. In Gram-positive bacteria, such as Streptococcus pneumoniae, ComA is a conserved efflux pump responsible for the maturation and secretion of peptide signals, including the competence-stimulating peptide (CSP), yet its structure and function remain unclear. Here, we functionally characterize ComA as an ABC transporter with high ATP affinity and determined its cryo-EM structures in the presence or absence of CSP or nucleotides. Our findings reveal a network of strong electrostatic interactions unique to ComA at the intracellular gate, a putative binding pocket for two CSP molecules, and negatively charged residues facilitating CSP translocation. Mutations of these residues affect ComA's peptidase activity in-vitro and prevent CSP export in-vivo. We demonstrate that ATP-Mg2+ triggers the outward-facing conformation of ComA for CSP release, rather than ATP alone. Our study provides molecular insights into the QS signal peptide secretion, highlighting potential targets for QS-targeting drugs.
Collapse
Affiliation(s)
- Lin Yu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Institute of Translational Medicine, Medical College, Yangzhou University, Yangzhou, 225001, Jiangsu, China
| | - Xin Xu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Wan-Zhen Chua
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore
| | - Hao Feng
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Zheng Ser
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Kai Shao
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Jian Shi
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore
| | - Yumei Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Science, Beijing, 100190, China
| | - Zongli Li
- Harvard Cryo-EM Center for Structural Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Radoslaw M Sobota
- Functional Proteomics Laboratory, SingMass National Laboratory, Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), Singapore, 138673, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545, Singapore.
| | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore.
- Center for Bioimaging Sciences, Department of Biological Sciences, National University of Singapore, Singapore, 117543, Singapore.
| |
Collapse
|
4
|
Fosfomycin Resistance Evolutionary Pathways of Stenotrophomonas maltophilia in Different Growing Conditions. Int J Mol Sci 2022; 23:ijms23031132. [PMID: 35163052 PMCID: PMC8835530 DOI: 10.3390/ijms23031132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 12/24/2022] Open
Abstract
The rise of multidrug-resistant Gram-negative pathogens and the lack of novel antibiotics to address this problem has led to the rescue of old antibiotics without a relevant use, such as fosfomycin. Stenotrophomonas maltophilia is a Gram-negative, non-fermenter opportunistic pathogen that presents a characteristic low susceptibility to several antibiotics of common use. Previous work has shown that while the so-far described mechanisms of fosfomycin resistance in most bacteria consist of the inactivation of the target or the transporters of this antibiotic, as well as the production of antibiotic-inactivating enzymes, these mechanisms are not selected in S. maltophilia fosfomycin-resistant mutants. In this microorganism, fosfomycin resistance is caused by the inactivation of enzymes belonging to its central carbon metabolism, hence linking metabolism with antibiotic resistance. Consequently, it is relevant to determine how different growing conditions, including urine and synthetic sputum medium that resemble infection, could impact the evolutionary pathways towards fosfomycin resistance in S. maltophilia. Our results show that S. maltophilia is able to acquire high-level fosfomycin resistance under all tested conditions. However, although some of the genetic changes leading to resistance are common, there are specific mutations that are selected under each of the tested conditions. These results indicate that the pathways of S. maltophilia evolution can vary depending on the infection point and provide information for understanding in more detail the routes of fosfomycin resistance evolution in S. maltophilia.
Collapse
|
5
|
Feng Z, Liu D, Wang L, Wang Y, Zang Z, Liu Z, Song B, Gu L, Fan Z, Yang S, Chen J, Cui Y. A Putative Efflux Transporter of the ABC Family, YbhFSR, in Escherichia coli Functions in Tetracycline Efflux and Na +(Li +)/H + Transport. Front Microbiol 2020; 11:556. [PMID: 32390957 PMCID: PMC7190983 DOI: 10.3389/fmicb.2020.00556] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 03/16/2020] [Indexed: 12/20/2022] Open
Abstract
ATP-binding cassette transporters are ubiquitous in almost all organisms. The Escherichia coli genome is predicted to encode 69 ABC transporters. Eleven of the ABC transporters are presumed to be exporters, of which seven are possible drug export transporters. There has been minimal research on the function of YbhFSR, which is one of the putative drug resistance exporters. In this study, the ybhF gene of this transporter was characterized. Overexpression and knockout strains of ybhF were constructed. The ATPase activity of YbhF was studied using the malachite green assay, and the efflux abilities of knockout strains were demonstrated by using ethidium bromide (EB) as a substrate. The substrates of YbhFSR efflux, examined with the minimum inhibitory concentration (MIC), were determined to be tetracycline, oxytetracycline, chlortetracycline, doxycycline, EB, and Hoechst33342. Furthermore, tetracycline and EB efflux and accumulation experiments confirmed that the substrates of YbhFSR were tetracyclines and EB. The MIC assay and the fluorescence test results showed that tetracyclines are likely to be the major antibiotic substrate of YbhFSR. The existence of the signature NatA motif suggested that YbhFSR may also function as a Na+/H+ transporter. Overexpression of YbhF in E. coli KNabc lacking crucial Na+/H+ transporters conferred tolerance to NaCl, LiCl, and an alkaline pH. Together, the results showed that YbhFSR exhibited dual functions as a drug efflux pump and a Na+ (Li+)/H+ antiporter.
Collapse
Affiliation(s)
- Zhenyue Feng
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Defu Liu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Lizi Wang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yanhong Wang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Zhongjing Zang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Zhenhua Liu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Baifen Song
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Liwei Gu
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Zhaowei Fan
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Siyu Yang
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Jing Chen
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| | - Yudong Cui
- College of Life Science and Technology, Heilongjiang Bayi Agricultural University, Daqing, China
| |
Collapse
|
6
|
Substrate polyspecificity and conformational relevance in ABC transporters: new insights from structural studies. Biochem Soc Trans 2018; 46:1475-1484. [PMID: 30514765 DOI: 10.1042/bst20180146] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 10/09/2018] [Accepted: 10/30/2018] [Indexed: 12/17/2022]
Abstract
Transport of molecules and ions across biological membranes is an essential process in all organisms. It is carried out by a range of evolutionarily conserved primary and secondary transporters. A significant portion of the primary transporters belong to the ATP-binding cassette (ABC) superfamily, which utilise the free-energy from ATP hydrolysis to shuttle many different substrates across various biological membranes, and consequently, are involved in both normal and abnormal physiology. In humans, ABC transporter-associated pathologies are perhaps best exemplified by multidrug-resistance transporters that efflux many xenobiotic compounds due to their remarkable substrate polyspecificity. Accordingly, understanding the transport mechanism(s) is of great significance, and indeed, much progress has been made in recent years, particularly from structural studies on ABC exporters. Consequently, the general mechanism of 'alternate access' has been modified to describe individual transporter nuances, though some aspects of the transport process remain unclear. Moreover, as new information has emerged, the physiological relevance of the 'open-apo' conformation of MsbA (a bacterial exporter) has been questioned and, by extension, its contribution to mechanistic models. We present here a comprehensive overview of the most recently solved structures of ABC exporters, focusing on new insights regarding the nature of substrate polyspecificity and the physiological relevance of the 'open-apo' conformation. This review evaluates the claim that the latter may be an artefact of detergent solubilisation, and we hypothesise that the biophysical properties of the membrane play a key role in the function of ABC exporters allowing them to behave like a 'spring-hinge' during their transport cycle.
Collapse
|
7
|
Li XT, Ju RJ, Li XY, Zeng F, Shi JF, Liu L, Zhang CX, Sun MG, Lou JN, Lu WL. Multifunctional targeting daunorubicin plus quinacrine liposomes, modified by wheat germ agglutinin and tamoxifen, for treating brain glioma and glioma stem cells. Oncotarget 2015; 5:6497-511. [PMID: 25153726 PMCID: PMC4171646 DOI: 10.18632/oncotarget.2267] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Most anticancer drugs are not able to cross the blood-brain barrier (BBB) effectively while surgery and radiation therapy cannot eradicate brain glioma cells and glioma stem cells (GSCs), hence resulting in poor prognosis with high recurrence rates. In the present study, a kind of multifunctional targeting daunorubicin plus quinacrine liposomes was developed for treating brain glioma and GSCs. Evaluations were performed on in-vitro BBB model, murine glioma cells, GSCs, and GSCs bearing mice. Results showed that the multifunctional targeting daunorubicin plus quinacrine liposomes exhibited evident capabilities in crossing the BBB, in killing glioma cells and GSCs and in diminishing brain glioma in mice. Action mechanism studies indicated that the enhanced efficacy of the multifunctional targeting drugs-loaded liposomes could be due to the following aspects: evading the rapid elimination from blood circulation; crossing the BBB effectively; improving drug uptake by glioma cells and GSCs; down-regulating the overexpressed ABC transporters; inducing apoptosis of GSCs via up-regulating apoptotic receptor/ligand (Fas/Fasl), activating apoptotic enzymes (caspases 8, 9 and 3), activating pro-apoptotic proteins (Bax and Bok), activating tumor suppressor protein (P53) and suppressing anti-apoptotic proteins (Bcl-2 and Mcl-1). In conclusion, the multifunctional targeting daunorubicin plus quinacrine liposomes could be used as a potential therapy for treating brain glioma and GSCs.
Collapse
Affiliation(s)
- Xue-Tao Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China; School of Pharmacy, Liaoning University of Traditional Chinese Medicine, Dalian, China
| | - Rui-Jun Ju
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Xiu-Ying Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Fan Zeng
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Ji-Feng Shi
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Lei Liu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Cheng-Xiang Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Meng-Ge Sun
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| | - Jin-Ning Lou
- Institute of Clinical Medical Sciences, Chia-Japan Friendship Hospital, The Ministry of Health, Beijing, China
| | - Wan-Liang Lu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, China
| |
Collapse
|
8
|
Abstract
Anthracyclines have received significant attention due to their effectiveness and extensive use as anticancer agents. At present, the clinical use of these drugs is offset by drug resistance in tumours and cardiotoxicity. Therefore, a relentless search for the 'better anthracycline' has been ongoing since the inception of these drugs > 30 years ago. This review focuses on the most recent pharmacology and medicinal chemistry developments on the design and use of anthracyclines. Based on their crystal structures as well as molecular modelling, a more detailed mechanism of topoisomerase poisoning by these new anthracyclines has emerged. Chemical modifications of anthracyclines have been found to possibly change the target selectivity among various topoisomerases and, thus, vary their anticancer activity. Additionally, recent sugar modifications of anthracyclines have also been found to overcome P-glycoprotein-mediated drug resistance in cancer therapy. The continued improvement of anthracycline clinical applications so far and the clinical trials of the 'third generation' of anthracyclines (such as sabarubicin) are also discussed. To finally find the 'better' anthracycline, further areas of research still need to be explored such as: the elucidation of the topoisomerase and P-glycoprotein crystal structures, molecular modelling based on crystal structure in order to design the next generation of better anthracycline drugs, the continued modifications of the anthracycline sugar moieties, and the further improvement of anthracycline drug delivery methods.
Collapse
Affiliation(s)
- Janos Nadas
- Department of Chemistry, College of Pharmacy, The Ohio Sate University, Columbus, OH 43210, USA
| | | |
Collapse
|
9
|
Affiliation(s)
- Suguru Okuda
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138;
| | - Hajime Tokuda
- Faculty of Nutritional Sciences, University of Morioka, Takizawa, Iwate 020-0183, Japan;
| |
Collapse
|
10
|
|
11
|
Mi Y, Zheng PY, Zhang BY, Liu ZQ, Song CH, Yang PC. Role of ABC transporter genes msbA and spab in multidrug resistance of Helicobacter pylori. Shijie Huaren Xiaohua Zazhi 2011; 19:1500-1505. [DOI: 10.11569/wcjd.v19.i14.1500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
AIM: To evaluate the potential role of ATP-binding cassette (ABC) transporter genes msbA and spab in multidrug resistance (MDR) of Helicobacter pylori (H.pylori).
METHODS: H.pylori strains were isolated from patients with peptic ulcer or gastritis. The minimal inhibitory concentrations (MICs) of ampicillin, ceftriaxone, tetracycline, clarithromycin, ofloxacin and furazolidone for H.pylori strains were determined by agar dilution test. Five sensitive H.pylori strains (four is H.pylori olates and one standard strain NCTC11637) were used to induce multidrug resistance with chloramphenicol. The mRNA expression of msbA and spab in these multidrug-resistant strains was determined by RT-PCR. Two H.pylori gene knockout mutants (MZ1006ΔmsbA and MZ1006Δspab) were constructed by inserting the kanamycin resistance cassette from the pEGFP-N2 vector into the msbA and spab genes, and their susceptibility profiles to nine antibiotics were estimated.
RESULTS: The expression levels of ABC transporter genes msbA and spab in multidrug-resistant H.pylori strains were higher than those in sensitive strains (1.8200 ± 0.5310 vs 0.8420 ± 0.0789, P = 0.018, for msbA; 1.8340 ± 0.2726 vs 1.2180 ± 0.0743, P = 0.015, for spab). MZ1006ΔmsbA and H.pylori MZ1006spab mutants were constructed successfully, and their sensitivity to four of nine antibiotics was significantly enhanced compared to their parental wild-type strains. Both the msbA and spab genes were detected in all isolated strains.
CONCLUSION: ABC transporter genes msbA and spab play an important role in multidrug resistance of H.pylori.
Collapse
|
12
|
Louie RJ, Pagant S, Youn JY, Halliday JJ, Huyer G, Michaelis S, Miller EA. Functional rescue of a misfolded eukaryotic ATP-binding cassette transporter by domain replacement. J Biol Chem 2010; 285:36225-34. [PMID: 20843810 DOI: 10.1074/jbc.m110.160523] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
ATP-binding cassette (ABC) transporters are integral membrane proteins that couple ATP binding/hydrolysis with the transport of hydrophilic substrates across lipid barriers. Deletion of Phe-670 in the first nucleotide-binding domain (NBD1) of the yeast ABC transporter, Yor1p, perturbs interdomain associations, reduces functionality, and hinders proper transport to the plasma membrane. Functionality of Yor1p-ΔF was restored upon co-expression of a peptide containing wild-type NBD1. To gain insight into the biogenesis of this important class of proteins, we defined the requirements for this rescue. We show that a misfolding lesion in NBD1 of the full-length protein is a prerequisite for functional rescue by exogenous NBD1, which is mediated by physical replacement of the dysfunctional domain by the soluble NBD1. This association does not restore trafficking of Yor1p-ΔF but instead confers catalytic activity to the small population of Yor1p-ΔF that escapes to the plasma membrane. An important coupling between the exogenous NBD1 and ICL4 within full-length aberrant Yor1p-ΔF is required for functional rescue but not for the physical interaction between the two polypeptides. Together, our genetic and biochemical data reveal that it is possible to modulate activity of ABC transporters by physically replacing dysfunctional domains.
Collapse
Affiliation(s)
- Raymond J Louie
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | | | | | | | | | | | | |
Collapse
|
13
|
Igarashi S, Osawa M, Ozawa SI, Shimada I. Backbone resonance assignments for the ligand binding subunit of the histidine permease complex (HisJ) from Escherichia coli, under histidine-bound and unbound states. BIOMOLECULAR NMR ASSIGNMENTS 2010; 4:17-20. [PMID: 19921465 DOI: 10.1007/s12104-009-9200-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Accepted: 11/05/2009] [Indexed: 05/28/2023]
Abstract
HisJ is a histidine binding subunit of the histidine permease, which exists in the outer membrane of Gram-negative bacteria. In order to incorporate the periplasmic histidine into the cell, HisJ captures histidine in the periplasm, and transfers the histidine to the transmembrane complex of histidine permease that is an ABC transporter. We established the backbone resonance assignments of (1)H/(13)C/(15)N-labeled HisJ from Escherichia coli, in the histidine-bound and unbound states.
Collapse
Affiliation(s)
- Shunsuke Igarashi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | | | | | | |
Collapse
|
14
|
Zgurskaya HI. Multicomponent drug efflux complexes: architecture and mechanism of assembly. Future Microbiol 2009; 4:919-32. [PMID: 19722844 DOI: 10.2217/fmb.09.62] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Multidrug efflux pumps are major contributors to intrinsic antibiotic resistance in Gram-negative pathogens. The basic structure of these pumps comprises an inner membrane transporter, a periplasmic membrane fusion protein and an outer membrane channel. However, the architecture and composition of multidrug efflux complexes vary significantly because of the topological and functional diversity of the inner membrane transporters. This article presents the current views on architecture and assembly of multicomponent drug efflux transporters from Gram-negative bacteria.
Collapse
Affiliation(s)
- Helen I Zgurskaya
- Department of Chemistry & Biochemistry, University of Oklahoma, 620 Parrington Oval, Room 208, Norman, OK 73019, USA.
| |
Collapse
|
15
|
Chiu HC, Lin TL, Yang JC, Wang JT. Synergistic effect of imp/ostA and msbA in hydrophobic drug resistance of Helicobacter pylori. BMC Microbiol 2009; 9:136. [PMID: 19594901 PMCID: PMC2719649 DOI: 10.1186/1471-2180-9-136] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2009] [Accepted: 07/13/2009] [Indexed: 11/22/2022] Open
Abstract
Background Contamination of endoscopy equipment by Helicobacter pylori (H. pylori) frequently occurs after endoscopic examination of H. pylori-infected patients. In the hospital, manual pre-cleaning and soaking in glutaraldehyde is an important process to disinfect endoscopes. However, this might not be sufficient to remove H. pylori completely, and some glutaraldehyde-resistant bacteria might survive and be passed to the next patient undergoing endoscopic examination through unidentified mechanisms. We identified an Imp/OstA protein associated with glutaraldehyde resistance in a clinical strain, NTUH-C1, from our previous study. To better understand and manage the problem of glutaraldehyde resistance, we further investigated its mechanism. Results The minimal inhibitory concentrations (MICs) of glutaraldehyde andexpression of imp/ostA RNA in 11 clinical isolates from the National Taiwan University Hospital were determined. After glutaraldehyde treatment, RNA expression in the strains with the MICs of 4–10 μg/ml was higher than that in strains with the MICs of 1–3 μg/ml. We examined the full-genome expression of strain NTUH-S1 after glutaraldehyde treatment using a microarray and found that 40 genes were upregulated and 31 genes were downregulated. Among the upregulated genes, imp/ostA and msbA, two putative lipopolysaccharide biogenesis genes, were selected for further characterization. The sensitivity to glutaraldehyde or hydrophobic drugs increased in both of imp/ostA and msbA single mutants. The imp/ostA and msbA double mutant was also hypersensitive to these chemicals. The lipopolysaccharide contents decreased in individual imp/ostA and msbA mutants and dramatically reduced in the imp/ostA and msbA double mutant. Outer membrane permeability assay demonstrated that the imp/ostA and msbA double mutation resulted in the increase of outer membrane permeability. Ethidium bromide accumulation assay demonstrated that MsbA was involved in efflux of hydrophobic drugs. Conclusion The expression levels of imp/ostA and msbA were correlated with glutaraldehyde resistance in clinical isolates after glutaraldehyde treatment. Imp/OstA and MsbA play a synergistic role in hydrophobic drugs resistance and lipopolysaccharide biogenesis in H. pylori.
Collapse
Affiliation(s)
- Hung-Chuan Chiu
- Department of Microbiology, National Taiwan University College of Medicine, Taipei City 10051, Taiwan, Republic of China.
| | | | | | | |
Collapse
|
16
|
Futatsumori-Sugai M, Abe R, Watanabe M, Kudou M, Yamamoto T, Ejima D, Arakawa T, Tsumoto K. Utilization of Arg-elution method for FLAG-tag based chromatography. Protein Expr Purif 2009; 67:148-55. [PMID: 19362151 DOI: 10.1016/j.pep.2009.03.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2009] [Revised: 03/28/2009] [Accepted: 03/30/2009] [Indexed: 11/25/2022]
Abstract
FLAG-tag is one of the commonly used purification technologies for recombinant proteins. An antibody, M2, specifically binds to the FLAG-tag whether it is attached to N- or C-terminus of proteins to be purified. The bound proteins are generally eluted by competition with a large excess of free FLAG peptide. This requires synthetic FLAG peptide and also removal of bound FLAG peptide for M2 column regeneration. We have shown before that arginine at mild pH can effectively dissociate protein-protein or protein-ligand interactions, e.g. in Protein-A, antigen and dye-affinity chromatography. We have tested here elution of FLAG-fused proteins by arginine for columns of M2-immobilized resin using several proteins in comparison with competitive elution by FLAG peptide or low pH glycine buffer. Active and folded proteins were successfully and effectively eluted using 0.5-1M arginine at pH 3.5-4.4, as reported in this paper.
Collapse
Affiliation(s)
- Mutsumi Futatsumori-Sugai
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, Kashiwa 277-8562, Japan
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Yaffe E, Fishelovitch D, Wolfson HJ, Halperin D, Nussinov R. MolAxis: efficient and accurate identification of channels in macromolecules. Proteins 2009; 73:72-86. [PMID: 18393395 DOI: 10.1002/prot.22052] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Channels and cavities play important roles in macromolecular functions, serving as access/exit routes for substrates/products, cofactor and drug binding, catalytic sites, and ligand/protein. In addition, channels formed by transmembrane (TM) proteins serve as transporters and ion channels. MolAxis is a new sensitive and fast tool for the identification and classification of channels and cavities of various sizes and shapes in macromolecules. MolAxis constructs corridors, which are pathways that represent probable routes taken by small molecules passing through channels. The outer medial axis of the molecule is the collection of points that have more than one closest atom. It is composed of two-dimensional surface patches and can be seen as a skeleton of the complement of the molecule. We have implemented in MolAxis a novel algorithm that uses state-of-the-art computational geometry techniques to approximate and scan a useful subset of the outer medial axis, thereby reducing the dimension of the problem and consequently rendering the algorithm extremely efficient. MolAxis is designed to identify channels that connect buried cavities to the outside of macromolecules and to identify TM channels in proteins. We apply MolAxis to enzyme cavities and TM proteins. We further utilize MolAxis to monitor channel dimensions along Molecular Dynamics trajectories of a human Cytochrome P450. MolAxis constructs high quality corridors for snapshots at picosecond time-scale intervals substantiating the gating mechanism in the 2e substrate access channel. We compare our results with previous tools in terms of accuracy, performance and underlying theoretical guarantees of finding the desired pathways. MolAxis is available on line as a web-server and as a stand alone easy-to-use program (http://bioinfo3d.cs.tau.ac.il/MolAxis/).
Collapse
Affiliation(s)
- Eitan Yaffe
- School of Computer Science, Raymond and Beverly Sackler Faculty for Exact Science, Tel Aviv University, Tel Aviv 69978, Israel
| | | | | | | | | |
Collapse
|
18
|
Kamakura A, Fujimoto Y, Motohashi Y, Ohashi K, Ohashi-Kobayashi A, Maeda M. Functional dissection of transmembrane domains of human TAP-like (ABCB9). Biochem Biophys Res Commun 2008; 377:847-51. [DOI: 10.1016/j.bbrc.2008.10.078] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2008] [Accepted: 10/15/2008] [Indexed: 11/24/2022]
|
19
|
Sharom FJ. ABC multidrug transporters: structure, function and role in chemoresistance. Pharmacogenomics 2008; 9:105-27. [PMID: 18154452 DOI: 10.2217/14622416.9.1.105] [Citation(s) in RCA: 692] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Three ATP-binding cassette (ABC)-superfamily multidrug efflux pumps are known to be responsible for chemoresistance; P-glycoprotein (ABCB1), MRP1 (ABCC1) and ABCG2 (BCRP). These transporters play an important role in normal physiology by protecting tissues from toxic xenobiotics and endogenous metabolites. Hydrophobic amphipathic compounds, including many clinically used drugs, interact with the substrate-binding pocket of these proteins via flexible hydrophobic and H-bonding interactions. These efflux pumps are expressed in many human tumors, where they likely contribute to resistance to chemotherapy treatment. However, the use of efflux-pump modulators in clinical cancer treatment has proved disappointing. Single nucleotide polymorphisms in ABC drug-efflux pumps may play a role in responses to drug therapy and disease susceptibility. The effect of various genotypes and haplotypes on the expression and function of these proteins is not yet clear, and their true impact remains controversial.
Collapse
Affiliation(s)
- Frances J Sharom
- University of Guelph, Department of Molecular & Cellular Biology, Guelph Ontario, N1G 2W1, Canada.
| |
Collapse
|
20
|
Abstract
High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as "Trojan horse" toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.
Collapse
Affiliation(s)
- Marcus Miethke
- Philipps Universität Marburg, FB Chemie Biochemie, Hans Meerwein Strasse, D-35032 Marburg, Germany
| | | |
Collapse
|
21
|
Federici L, Woebking B, Velamakanni S, Shilling RA, Luisi B, van Veen HW. New structure model for the ATP-binding cassette multidrug transporter LmrA. Biochem Pharmacol 2007; 74:672-8. [PMID: 17624317 DOI: 10.1016/j.bcp.2007.05.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2007] [Revised: 05/11/2007] [Accepted: 05/21/2007] [Indexed: 12/14/2022]
Abstract
Multidrug resistance of pathogenic microorganisms and mammalian tumors can be associated with the overexpression of multidrug transporters. These integral membrane proteins are capable of extruding a wide range of structurally unrelated compounds from the cell. Among the different classes of multidrug transporters are the ATP binding cassette (ABC) transporters, which are dependent on the binding and hydrolysis of ATP. In the past five years, many researchers have built homology models of ABC extrusion systems using the atomic coordinates of crystallized MsbA, a lipopolysaccharide transporter in Gram-negative bacteria. Likewise, we have previously used the Vibrio cholera MsbA structure as a template in the modeling of the multidrug transporter LmrA from Lactococcus lactis. In view of the recently discovered inaccuracies in the MsbA structure, we have remodelled LmrA using the atomic coordinates of the MsbA homologue Sav1866 from Staphylococcus aureus. To compare and test our MsbA-based and Sav1866-based LmrA models we performed cysteine cross-linking at three key positions in LmrA. The pattern of cross-linking at these positions was consistent with the overall topology of transmembrane helices in Sav1866, suggesting that its crystal structure might be physiologically relevant. We recently identified E314 as a residue important in proton conduction by LmrA. The predicted location of this residue at the interface between the two half-transporters in the Sav1866-based homodimer, within the inner leaflet of the phospholipid bilayer, provides a new structural basis for the role of E314 in LmrA-mediated transport.
Collapse
Affiliation(s)
- Luca Federici
- Ce.S.I. Centro Studi sull'Invecchiamento, Fondazione Universita' G. D'Annunzio, Via Colle dell'Ara, 66013 Chieti, Italy
| | | | | | | | | | | |
Collapse
|
22
|
Nnadi CU, Malhotra AK. Individualizing antipsychotic drug therapy in schizophrenia: the promise of pharmacogenetics. Curr Psychiatry Rep 2007; 9:313-8. [PMID: 17880863 PMCID: PMC2276697 DOI: 10.1007/s11920-007-0038-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The first- and second-generation antipsychotic drugs have become mainstay drug treatment for schizophrenia. However, patients who receive antipsychotic drugs differ with respect to treatment response and drug-induced adverse events. The biological predictors of treatment response are being researched worldwide, with emphasis on molecular genetic predictors of treatment response. Because of the rapid and exciting developments in the field, we reviewed the recent studies of the molecular genetic basis of treatment response in schizophrenia. The accumulating data suggest that DNA information in the pathways for drug metabolism and drug target sites may be an important predictor of treatment response in schizophrenia. The data suggest that clinicians may soon be using a patient's genotype to decide initial choice of antipsychotic drug treatment in schizophrenia. The pharmacogenetics of schizophrenia can improve the prospects of individualized treatment and drug discovery. Pharmacogenetic investigations of schizophrenia susceptibility loci, and genes controlling drug target site receptors, drug-metabolizing enzymes, the blood-brain barrier systems, and epigenetic mechanisms could lead to a molecular classification of treatment response and adverse events of psychotropic drugs.
Collapse
|
23
|
Lee JH, Harvat EM, Stevens JM, Ferguson SJ, Saier MH. Evolutionary origins of members of a superfamily of integral membrane cytochrome c biogenesis proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:2164-81. [PMID: 17706591 DOI: 10.1016/j.bbamem.2007.04.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2006] [Revised: 03/22/2007] [Accepted: 04/24/2007] [Indexed: 11/20/2022]
Abstract
We have analyzed the relationships of homologues of the Escherichia coli CcmC protein for probable topological features and evolutionary relationships. We present bioinformatic evidence suggesting that the integral membrane proteins CcmC (E. coli; cytochrome c biogenesis System I), CcmF (E. coli; cytochrome c biogenesis System I) and ResC (Bacillus subtilis; cytochrome c biogenesis System II) are all related. Though the molecular functions of these proteins have not been fully described, they appear to be involved in the provision of heme to c-type cytochromes, and so we have named them the putative Heme Handling Protein (HHP) family (TC #9.B.14). Members of this family exhibit 6, 8, 10, 11, 13 or 15 putative transmembrane segments (TMSs). We show that intragenic triplication of a 2 TMS element gave rise to a protein with a 6 TMS topology, exemplified by CcmC. This basic 6 TMS unit then gave rise to two distinct types of proteins with 8 TMSs, exemplified by ResC and the archaeal CcmC, and these further underwent fusional or insertional events yielding proteins with 10, 11 and 13 TMSs (ResC homologues) as well as 15 TMSs (CcmF homologues). Specific evolutionary pathways taken are proposed. This work provides the first evidence for the pathway of appearance of distantly related proteins required for post-translational maturation of c-type cytochromes in bacteria, plants, protozoans and archaea.
Collapse
Affiliation(s)
- Jong-Hoon Lee
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | | | | | | | | |
Collapse
|
24
|
Sauna ZE, Ambudkar SV. About a switch: how P-glycoprotein (ABCB1) harnesses the energy of ATP binding and hydrolysis to do mechanical work. Mol Cancer Ther 2007; 6:13-23. [PMID: 17237262 DOI: 10.1158/1535-7163.mct-06-0155] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The efflux of drugs by the multidrug transporter P-glycoprotein (Pgp; ABCB1) is one of the principal means by which cancer cells evade chemotherapy and exhibit multidrug resistance. Mechanistic studies of Pgp-mediated transport, however, transcend the importance of this protein per se as they help us understand the transport pathway of the ATP-binding cassette proteins in general. The ATP-binding cassette proteins comprise one of the largest protein families, are central to cellular physiology, and constitute important drug targets. The functional unit of Pgp consists of two nucleotide-binding domains (NBD) and two transmembrane domains that are involved in the transport of drug substrates. Early studies postulated that conformational changes as a result of ATP hydrolysis were transmitted to the transmembrane domains bringing about drug transport. More recent structural and biochemical studies on the other hand suggested that ATP binds at the interface of the two NBDs and induces the formation of a closed dimer, and it has been hypothesized that this dimerization and subsequent ATP hydrolysis powers transport. Based on the mutational and biochemical work on Pgp and structural studies with isolated NBDs, we review proposed schemes for the catalytic cycle of ATP hydrolysis and the transport pathway.
Collapse
Affiliation(s)
- Zuben E Sauna
- Laboratory of Cell Biology, Center for Cancer Research, National Cancer Institute, NIH, Building 37, Room 2120, 37 Convent Drive, Bethesda, MD 20892-4256, USA
| | | |
Collapse
|
25
|
Sonne J, Kandt C, Peters GH, Hansen FY, Jensen MØ, Tieleman DP. Simulation of the coupling between nucleotide binding and transmembrane domains in the ATP binding cassette transporter BtuCD. Biophys J 2007; 92:2727-34. [PMID: 17208973 PMCID: PMC1831707 DOI: 10.1529/biophysj.106.097972] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The nucleotide-induced structural rearrangements in ATP binding cassette (ABC) transporters, leading to substrate translocation, are largely unknown. We have modeled nucleotide binding and release in the vitamin B(12) importer BtuCD using perturbed elastic network calculations and biased molecular dynamics simulations. Both models predict that nucleotide release decreases the tilt between the two transmembrane domains and opens the cytoplasmic gate. Nucleotide binding has the opposite effect. The observed coupling may be relevant for all ABC transporters because of the conservation of nucleotide binding domains and the shared role of ATP in ABC transporters. The rearrangements in the cytoplasmic gate region do not provide enough space for B(12) to diffuse from the transporter pore into the cytoplasm, which could suggest that peristaltic forces are needed to exclude B(12) from the transporter pore.
Collapse
Affiliation(s)
- Jacob Sonne
- Department of Chemistry, Technical University of Denmark, DK-2800 Lyngby, Denmark
| | | | | | | | | | | |
Collapse
|
26
|
Battisti RF, Zhong Y, Fang L, Gibbs S, Shen J, Nadas J, Zhang G, Sun D. Modifying the Sugar Moieties of Daunorubicin Overcomes P-gp-Mediated Multidrug Resistance. Mol Pharm 2006; 4:140-53. [PMID: 17274671 DOI: 10.1021/mp060075v] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Anthracyclines are widely used in patients for anticancer activity. However, one of the limitations for their clinical use is P-gp-mediated drug resistance in cancer therapy. We hypothesize that modified anthracyclines will retain their anticancer activity, avert P-gp binding, and thus overcome P-gp-mediated drug resistance. Twenty-five daunorubicin analogues were synthesized with slight structure modifications in sugar moieties. Molecular docking, cytotoxicity, and P-gp inhibition assays in drug-resistant leukemia cells (K562/Dox) were used to identify several candidates that avert binding to multidrug-resistant protein (MsbA) and overcome drug resistance. Molecular docking showed that daunorubicin bound to the cavity between the intracellular domain (ICD) and nucleoside binding domain (NBD) of MsbA, which might be the "entry site" for the transport of its substrate. The molecular docking accurately predicted the substrates of multidrug-resistant protein. Several aspects are important for daunorubicin analogue binding to MsbA: (1) the substitution pattern and stereochemistry of the tetracyclic ring and sugar moiety; (2) the hydrogen bond donor or acceptor capability of the substituent at C'-3 and C'-4. Molecular docking, cytotoxicity, and P-gp inhibition assays identified ADNR, ADNR-1, and ADNR-3 for averting P-gp binding and overcoming drug resistance. The replacement of C'-3-NH2 with azido group in daunorubicin not only abolishes the hydrogen bond between the sugar moiety and MsbA but also completely changes the overall binding conformation, and thus averts the binding to MsbA. Cytotoxicity assays confirmed that these compounds showed high sensitivity against drug-resistant cancer cells (K562/Dox) with P-gp overexpression. P-gp inhibition assay indeed confirms that these appropriately modified compounds avert P-gp binding and thus overcome P-gp-mediated drug resistance.
Collapse
MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP-Binding Cassette Transporters/chemistry
- ATP-Binding Cassette Transporters/metabolism
- Bacterial Proteins/chemistry
- Bacterial Proteins/metabolism
- Carbohydrate Metabolism
- Cyclosporine/pharmacology
- Cytotoxicity, Immunologic
- Daunorubicin/analogs & derivatives
- Daunorubicin/chemistry
- Daunorubicin/metabolism
- Disaccharides/metabolism
- Drug Resistance, Multiple
- Drug Resistance, Neoplasm
- Gene Expression Regulation, Neoplastic
- Humans
- Inhibitory Concentration 50
- K562 Cells
- Monosaccharides/metabolism
- Protein Structure, Secondary
Collapse
Affiliation(s)
- Robert F Battisti
- Division of Pharmaceutics, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210, USA
| | | | | | | | | | | | | | | |
Collapse
|
27
|
Tieleman DP. Computer simulations of transport through membranes: passive diffusion, pores, channels and transporters. Clin Exp Pharmacol Physiol 2006; 33:893-903. [PMID: 17002665 DOI: 10.1111/j.1440-1681.2006.04461.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A key function of biological membranes is to provide mechanisms for the controlled transport of ions, nutrients, metabolites, peptides and proteins between a cell and its environment. We are using computer simulations to study several processes involved in transport. In model membranes, the distribution of small molecules can be accurately calculated; we are making progress towards understanding the factors that determine the partitioning behaviour in the inhomogeneous lipid environment, with implications for drug distribution, membrane protein folding and the energetics of voltage gating. Lipid bilayers can be simulated at a scale that is sufficiently large to study significant defects, such as those caused by electroporation. Computer simulations of complex membrane proteins, such as potassium channels and ATP-binding cassette (ABC) transporters, can give detailed information about the atomistic dynamics that form the basis of ion transport, selectivity, conformational change and the molecular mechanism of ATP-driven transport. This is illustrated in the present review with recent simulation studies of the voltage-gated potassium channel KvAP and the ABC transporter BtuCD.
Collapse
Affiliation(s)
- D Peter Tieleman
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
| |
Collapse
|
28
|
Oloo EO, Kandt C, O'Mara ML, Tieleman DP. Computer simulations of ABC transporter componentsThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB — Membrane Proteins in Health and Disease. Biochem Cell Biol 2006; 84:900-11. [PMID: 17215877 DOI: 10.1139/o06-182] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Current computer simulation techniques provide robust tools for studying the detailed structure and functional dynamics of proteins, as well as their interaction with each other and with other biomolecules. In this minireview, we provide an illustration of recent progress and future challenges in computer modeling by discussing computational studies of ATP-binding cassette (ABC) transporters. ABC transporters have multiple components that work in a well coordinated fashion to enable active transport across membranes. The mechanism by which members of this superfamily execute transport remains largely unknown. Molecular dynamics simulations initiated from high-resolution crystal structures of several ABC transporters have proven to be useful in the investigation of the nature of conformational coupling events that may drive transport. In addition, fruitful efforts have been made to predict unknown structures of medically relevant ABC transporters, such as P-glycoprotein, using homology-based computational methods. The various techniques described here are also applicable to gaining an atomically detailed understanding of the functional mechanisms of proteins in general.
Collapse
Affiliation(s)
- Eliud O Oloo
- Department of Biological Sciences, University of Calgary, 2500 University Dr. NW, Calgary, AB T2N 1N4, Canada
| | | | | | | |
Collapse
|
29
|
Ejendal KFK, Diop NK, Schweiger LC, Hrycyna CA. The nature of amino acid 482 of human ABCG2 affects substrate transport and ATP hydrolysis but not substrate binding. Protein Sci 2006; 15:1597-607. [PMID: 16815914 PMCID: PMC2242565 DOI: 10.1110/ps.051998406] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Several members of the ATP-binding cassette (ABC) transporter superfamily, including P-glycoprotein and the half-transporter ABCG2, can confer multidrug resistance to cancer cells in culture by functioning as ATP-dependent efflux pumps. ABCG2 variants harboring a mutation at arginine 482 have been cloned from several drug-resistant cell lines, and these variants differ in their substrate transport phenotype. In this study, we changed the wild-type arginine 482 in human ABCG2 to each one of the 19 other standard amino acids and expressed each one transiently in HeLa cells. Using the 5D3 antibody that recognizes a cell surface epitope of ABCG2, we observed that all the mutants were expressed at the cell surface. However, the mutant ABCG2 proteins differed markedly in transport activity. All of the variants were capable of transporting one or more of the substrates used in this study, with the exception of the R482K mutant, which is completely devoid of transport ability. Six of the mutants (R482G, R482H, R482K, R482P, R482T, and R482Y) and the wild-type protein (R482wt) were selected for studies of basal and stimulated ATPase activity and photoaffinity labeling with the substrate analog [125I]iodoarylazidoprazosin. Whereas these seven ABCG2 variants differed markedly in ATPase activity, all were able to specifically bind the substrate analog [125I]iodoarylazidoprazosin. These data suggest that residue 482 plays an important role in substrate transport and ATP turnover, but that the nature of this amino acid may not be important for substrate recognition and binding.
Collapse
Affiliation(s)
- Karin F K Ejendal
- Department of Chemistry and Purdue Cancer Center, Purdue University, West Lafayette, IN 47907, USA
| | | | | | | |
Collapse
|