1
|
Generating Genotype-Specific Aminoglycoside Combinations with Ceftazidime/Avibactam for KPC-Producing Klebsiella pneumoniae. Antimicrob Agents Chemother 2021; 65:e0069221. [PMID: 34152820 DOI: 10.1128/aac.00692-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Antibiotic combinations, including ceftazidime/avibactam (CAZ/AVI), are frequently employed to combat KPC-producing Klebsiella pneumoniae (KPC-Kp), though such combinations have not been rationally optimized. Clinical KPC-Kp isolates with common genes encoding aminoglycoside-modifying enzymes (AMEs), aac(6')-Ib' or aac(6')-Ib, were used in static time-kill assays (n = 4 isolates) and the hollow-fiber infection model (HFIM; n = 2 isolates) to evaluate the activity of gentamicin, amikacin, and CAZ/AVI alone and in combinations. A short course, one-time aminoglycoside dose was also evaluated. Gentamicin plus CAZ/AVI was then tested in a mouse pneumonia model. Synergy with CAZ/AVI was more common with amikacin for aac(6')-Ib'-containing KPC-Kp but more common with gentamicin for aac(6')-Ib-containing isolates in time-kill assays. In the HFIM, although the isolates were aminoglycoside-susceptible at baseline, aminoglycoside monotherapies displayed variable initial killing, followed by regrowth and resistance emergence. CAZ/AVI combined with amikacin or gentamicin resulted in undetectable counts 50 h sooner than CAZ/AVI monotherapy against KPC-Kp with aac(6')-Ib'. CAZ/AVI monotherapy failed to eradicate KPC-Kp with aac(6')-Ib and a combination with gentamicin led to undetectable counts 70 h sooner than with amikacin. A one-time aminoglycoside dose with CAZ/AVI provided similar killing to aminoglycosides dosed for 7 days. In the mouse pneumonia model (n = 1 isolate), gentamicin and CAZ/AVI achieved a 6.0-log10 CFU/lung reduction at 24 h, which was significantly greater than either monotherapy (P < 0.005). Aminoglycosides in combination with CAZ/AVI were promising for KPC-Kp infections; this was true even for a one-time aminoglycoside dose. Selecting aminoglycosides based on AME genes or susceptibilities can improve the pharmacodynamic activity of the combination.
Collapse
|
2
|
Zhang Q, Chi H, Wu L, Deng Z, Yu Y. Two Cryptic Self‐Resistance Mechanisms in
Streptomyces tenebrarius
Reveal Insights into the Biosynthesis of Apramycin. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Qian Zhang
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Hao‐Tian Chi
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Linrui Wu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Zixin Deng
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Yi Yu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| |
Collapse
|
3
|
Zhang Q, Chi H, Wu L, Deng Z, Yu Y. Two Cryptic Self‐Resistance Mechanisms in
Streptomyces tenebrarius
Reveal Insights into the Biosynthesis of Apramycin. Angew Chem Int Ed Engl 2021; 60:8990-8996. [DOI: 10.1002/anie.202100687] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Indexed: 12/30/2022]
Affiliation(s)
- Qian Zhang
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Hao‐Tian Chi
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Linrui Wu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Zixin Deng
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Yi Yu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| |
Collapse
|
4
|
Discovery of small-molecule inhibitors of multidrug-resistance plasmid maintenance using a high-throughput screening approach. Proc Natl Acad Sci U S A 2020; 117:29839-29850. [PMID: 33168749 DOI: 10.1073/pnas.2005948117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Carbapenem-resistant Enterobacteriaceae (CRE) are multidrug-resistant pathogens for which new treatments are desperately needed. Carbapenemases and other types of antibiotic resistance genes are carried almost exclusively on large, low-copy-number plasmids (pCRE). Accordingly, small molecules that efficiently evict pCRE plasmids should restore much-needed treatment options. We therefore designed a high-throughput screen to identify such compounds. A synthetic plasmid was constructed containing the plasmid replication machinery from a representative Escherichia coli CRE isolate as well as a fluorescent reporter gene to easily monitor plasmid maintenance. The synthetic plasmid was then introduced into an E. coli K12 tolC host. We used this screening strain to test a library of over 12,000 known bioactive agents for molecules that selectively reduce plasmid levels relative to effects on bacterial growth. From 366 screen hits we further validated the antiplasmid activity of kasugamycin, an aminoglycoside; CGS 15943, a nucleoside analog; and Ro 90-7501, a bibenzimidazole. All three compounds exhibited significant antiplasmid activity including up to complete suppression of plasmid replication and/or plasmid eviction in multiple orthogonal readouts and potentiated activity of the carbapenem, meropenem, against a strain carrying the large, pCRE plasmid from which we constructed the synthetic screening plasmid. Additionally, we found kasugamycin and CGS 15943 blocked plasmid replication, respectively, by inhibiting expression or function of the plasmid replication initiation protein, RepE. In summary, we validated our approach to identify compounds that alter plasmid maintenance, confer resensitization to antimicrobials, and have specific mechanisms of action.
Collapse
|
5
|
Kwapong AA, Stapleton P, Gibbons S. Inhibiting plasmid mobility: The effect of isothiocyanates on bacterial conjugation. Int J Antimicrob Agents 2019; 53:629-636. [PMID: 30685311 DOI: 10.1016/j.ijantimicag.2019.01.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 12/12/2018] [Accepted: 01/20/2019] [Indexed: 01/13/2023]
Abstract
Bacterial conjugation is the main mechanism for the transfer of multiple antimicrobial resistance genes among pathogenic micro-organisms. This process may be controlled by compounds that inhibit bacterial conjugation. In this study, the effects of allyl isothiocyanate, l-sulforaphane, benzyl isothiocyanate, phenylethyl isothiocyanate and 4-methoxyphenyl isothiocyanate on the conjugation of broad-host-range plasmids harbouring various antimicrobial resistance genes in Escherichia coli were investigated, namely plasmids pKM101 (IncN), TP114 (IncI2), pUB307 (IncP) and the low-copy-number plasmid R7K (IncW). Benzyl isothiocyanate (32 mg/L) significantly reduced conjugal transfer of pKM101, TP114 and pUB307 to 0.3 ± 0.6%, 10.7 ± 3.3% and 6.5 ± 1.0%, respectively. l-sulforaphane (16 mg/L; transfer frequency 21.5 ± 5.1%) and 4-methoxyphenyl isothiocyanate (100 mg/L; transfer frequency 5.2 ± 2.8%) were the only compounds showing anti-conjugal specificity by actively reducing the transfer of R7K and pUB307, respectively.
Collapse
Affiliation(s)
- Awo Afi Kwapong
- Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK; Department of Pharmaceutics and Microbiology, School of Pharmacy, University of Ghana, Accra, Ghana
| | - Paul Stapleton
- Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK
| | - Simon Gibbons
- Research Department of Pharmaceutical and Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX, UK.
| |
Collapse
|
6
|
Buckner MMC, Ciusa ML, Piddock LJV. Strategies to combat antimicrobial resistance: anti-plasmid and plasmid curing. FEMS Microbiol Rev 2018; 42:781-804. [PMID: 30085063 PMCID: PMC6199537 DOI: 10.1093/femsre/fuy031] [Citation(s) in RCA: 97] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/25/2018] [Indexed: 12/17/2022] Open
Abstract
Antimicrobial resistance (AMR) is a global problem hindering treatment of bacterial infections, rendering many aspects of modern medicine less effective. AMR genes (ARGs) are frequently located on plasmids, which are self-replicating elements of DNA. They are often transmissible between bacteria, and some have spread globally. Novel strategies to combat AMR are needed, and plasmid curing and anti-plasmid approaches could reduce ARG prevalence, and sensitise bacteria to antibiotics. We discuss the use of curing agents as laboratory tools including chemicals (e.g. detergents and intercalating agents), drugs used in medicine including ascorbic acid, psychotropic drugs (e.g. chlorpromazine), antibiotics (e.g. aminocoumarins, quinolones and rifampicin) and plant-derived compounds. Novel strategies are examined; these include conjugation inhibitors (e.g. TraE inhibitors, linoleic, oleic, 2-hexadecynoic and tanzawaic acids), systems designed around plasmid incompatibility, phages and CRISPR/Cas-based approaches. Currently, there is a general lack of in vivo curing options. This review highlights this important shortfall, which if filled could provide a promising mechanism to reduce ARG prevalence in humans and animals. Plasmid curing mechanisms which are not suitable for in vivo use could still prove important for reducing the global burden of AMR, as high levels of ARGs exist in the environment.
Collapse
Affiliation(s)
- Michelle M C Buckner
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham B15 2TT, UK
| | - Maria Laura Ciusa
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham B15 2TT, UK
| | - Laura J V Piddock
- Institute of Microbiology and Infection, College of Medical and Dental Sciences, The University of Birmingham B15 2TT, UK
| |
Collapse
|
7
|
Liu WQ, Amara P, Mouesca JM, Ji X, Renoux O, Martin L, Zhang C, Zhang Q, Nicolet Y. 1,2-Diol Dehydration by the Radical SAM Enzyme AprD4: A Matter of Proton Circulation and Substrate Flexibility. J Am Chem Soc 2018; 140:1365-1371. [DOI: 10.1021/jacs.7b10501] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Wan-Qiu Liu
- Department
of Chemistry, Fudan University, Shanghai 200433, China
| | | | | | - Xinjian Ji
- Department
of Chemistry, Fudan University, Shanghai 200433, China
| | | | | | - Chen Zhang
- Department
of Chemistry, Fudan University, Shanghai 200433, China
| | - Qi Zhang
- Department
of Chemistry, Fudan University, Shanghai 200433, China
| | | |
Collapse
|
8
|
Kamruzzaman M, Shoma S, Thomas CM, Partridge SR, Iredell JR. Plasmid interference for curing antibiotic resistance plasmids in vivo. PLoS One 2017; 12:e0172913. [PMID: 28245276 PMCID: PMC5330492 DOI: 10.1371/journal.pone.0172913] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/10/2017] [Indexed: 11/21/2022] Open
Abstract
Antibiotic resistance increases the likelihood of death from infection by common pathogens such as Escherichia coli and Klebsiella pneumoniae in developed and developing countries alike. Most important modern antibiotic resistance genes spread between such species on self-transmissible (conjugative) plasmids. These plasmids are traditionally grouped on the basis of replicon incompatibility (Inc), which prevents coexistence of related plasmids in the same cell. These plasmids also use post-segregational killing (‘addiction’) systems, which poison any bacterial cells that lose the addictive plasmid, to guarantee their own survival. This study demonstrates that plasmid incompatibilities and addiction systems can be exploited to achieve the safe and complete eradication of antibiotic resistance from bacteria in vitro and in the mouse gut. Conjugative ‘interference plasmids’ were constructed by specifically deleting toxin and antibiotic resistance genes from target plasmids. These interference plasmids efficiently cured the corresponding antibiotic resistant target plasmid from different Enterobacteriaceae in vitro and restored antibiotic susceptibility in vivo to all bacterial populations into which plasmid-mediated resistance had spread. This approach might allow eradication of emergent or established populations of resistance plasmids in individuals at risk of severe sepsis, enabling subsequent use of less toxic and/or more effective antibiotics than would otherwise be possible, if sepsis develops. The generalisability of this approach and its potential applications in bioremediation of animal and environmental microbiomes should now be systematically explored.
Collapse
Affiliation(s)
- Muhammad Kamruzzaman
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Shereen Shoma
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
| | - Christopher M. Thomas
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, United Kingdom
| | - Sally R. Partridge
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- Westmead Hospital, Westmead, New South Wales, Australia
| | - Jonathan R. Iredell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, The University of Sydney, Westmead, New South Wales, Australia
- Westmead Hospital, Westmead, New South Wales, Australia
- * E-mail:
| |
Collapse
|
9
|
Lv M, Ji X, Zhao J, Li Y, Zhang C, Su L, Ding W, Deng Z, Yu Y, Zhang Q. Characterization of a C3 Deoxygenation Pathway Reveals a Key Branch Point in Aminoglycoside Biosynthesis. J Am Chem Soc 2016; 138:6427-35. [PMID: 27120352 DOI: 10.1021/jacs.6b02221] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Apramycin is a clinically interesting aminoglycoside antibiotic (AGA) containing a highly unique bicyclic octose moiety, and this octose is deoxygenated at the C3 position. Although the biosynthetic pathways for most 2-deoxystreptamine-containing AGAs have been well characterized, the pathway for apramycin biosynthesis, including the C3 deoxygenation process, has long remained unknown. Here we report detailed investigation of apramycin biosynthesis by a series of genetic, biochemical and bioinformatical studies. We show that AprD4 is a novel radical S-adenosyl-l-methionine (SAM) enzyme, which uses a noncanonical CX3CX3C motif for binding of a [4Fe-4S] cluster and catalyzes the dehydration of paromamine, a pseudodisaccharide intermediate in apramycin biosynthesis. We also show that AprD3 is an NADPH-dependent reductase that catalyzes the reduction of the dehydrated product from AprD4-catalyzed reaction to generate lividamine, a C3' deoxygenated product of paromamine. AprD4 and AprD3 do not form a tight catalytic complex, as shown by protein complex immunoprecipitation and other assays. The AprD4/AprD3 enzyme system acts on different pseudodisaccharide substrates but does not catalyze the deoxygenation of oxyapramycin, an apramycin analogue containing a C3 hydroxyl group on the octose moiety, suggesting that oxyapramycin and apramycin are partitioned into two parallel pathways at an early biosynthetic stage. Functional dissection of the C6 dehydrogenase AprQ shows the crosstalk between different AGA biosynthetic gene clusters from the apramycin producer Streptomyces tenebrarius, and reveals the remarkable catalytic versatility of AprQ. Our study highlights the intriguing chemistry in apramycin biosynthesis and nature's ingenuity in combinatorial biosynthesis of natural products.
Collapse
Affiliation(s)
- Meinan Lv
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University , Wuhan, 430071, China
| | - Xinjian Ji
- Department of Chemistry, Fudan University , Shanghai, 200433, China
| | - Junfeng Zhao
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University , Wuhan, 430071, China.,Department of Chemistry, Fudan University , Shanghai, 200433, China
| | - Yongzhen Li
- Department of Chemistry, Fudan University , Shanghai, 200433, China
| | - Chen Zhang
- Department of Chemistry, Fudan University , Shanghai, 200433, China
| | - Li Su
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University , Wuhan, 430071, China
| | - Wei Ding
- Department of Chemistry, Fudan University , Shanghai, 200433, China
| | - Zixin Deng
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University , Wuhan, 430071, China
| | - Yi Yu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education), School of Pharmaceutical Sciences, Wuhan University , Wuhan, 430071, China
| | - Qi Zhang
- Department of Chemistry, Fudan University , Shanghai, 200433, China
| |
Collapse
|
10
|
Kudo F, Eguchi T. Aminoglycoside Antibiotics: New Insights into the Biosynthetic Machinery of Old Drugs. CHEM REC 2015; 16:4-18. [PMID: 26455715 DOI: 10.1002/tcr.201500210] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Indexed: 11/07/2022]
Abstract
2-Deoxystreptamine (2DOS) is the unique chemically stable aminocyclitol scaffold of clinically important aminoglycoside antibiotics such as neomycin, kanamycin, and gentamicin, which are produced by Actinomycetes. The 2DOS core can be decorated with various deoxyaminosugars to make structurally diverse pseudo-oligosaccharides. After the discovery of biosynthetic gene clusters for 2DOS-containing aminoglycoside antibiotics, the function of each biosynthetic enzyme has been extensively elucidated. The common biosynthetic intermediates 2DOS, paromamine and ribostamycin are constructed by conserved enzymes encoded in the gene clusters. The biosynthetic intermediates are then converted to characteristic architectures by unique enzymes encoded in each biosynthetic gene cluster. In this Personal Account, we summarize both common biosynthetic pathways and the pathways used for structural diversification.
Collapse
Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| |
Collapse
|
11
|
Woappi Y, Gabani P, Singh A, Singh OV. Antibiotrophs: The complexity of antibiotic-subsisting and antibiotic-resistant microorganisms. Crit Rev Microbiol 2014; 42:17-30. [PMID: 24495094 DOI: 10.3109/1040841x.2013.875982] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Widespread overuse of antibiotics has led to the emergence of numerous antibiotic-resistant bacteria; among these are antibiotic-subsisting strains capable of surviving in environments with antibiotics as the sole carbon source. This unparalleled expansion of antibiotic resistance reveals the potent and diversified resistance abilities of certain bacterial strains. Moreover, these strains often possess hypermutator phenotypes and virulence transmissibility competent for genomic and proteomic propagation and pathogenicity. Pragmatic and prospicient approaches will be necessary to develop efficient therapeutic methods against such bacteria and to understand the extent of their genomic adaptability. This review aims to reveal the niches of these antibiotic-catabolizing microbes and assesses the underlying factors linking natural microbial antibiotic production, multidrug resistance, and antibiotic-subsistence.
Collapse
Affiliation(s)
- Yvon Woappi
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| | - Prashant Gabani
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| | - Arya Singh
- b Department of Computer Science , Texas State University , San Marcos , TX , USA
| | - Om V Singh
- a Division of Biological and Health Sciences , University of Pittsburgh , Bradford , PA , USA and
| |
Collapse
|
12
|
Nash RP, McNamara DE, Ballentine WK, Matson SW, Redinbo MR. Investigating the impact of bisphosphonates and structurally related compounds on bacteria containing conjugative plasmids. Biochem Biophys Res Commun 2012; 424:697-703. [PMID: 22796221 DOI: 10.1016/j.bbrc.2012.07.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 07/04/2012] [Indexed: 11/16/2022]
Abstract
Bacterial plasmids propagate through microbial populations via the directed process of conjugative plasmid transfer (CPT). Because conjugative plasmids often encode antibiotic resistance genes and virulence factors, several approaches to inhibit CPT have been described. Bisphosphonates and structurally related compounds (BSRCs) were previously reported to disrupt conjugative transfer of the F (fertility) plasmid in Escherichia coli. We have further investigated the effect of these compounds on the transfer of two additional conjugative plasmids, pCU1 and R100, between E. coli cells. The impact of BSRCs on E. coli survival and plasmid transfer was found to be dependent on the plasmid type, the length of time the E. coli were exposed to the compounds, and the ratio of plasmid donor to plasmid recipient cells. Therefore, these data indicate that BSRCs produce a range of effects on the conjugative transfer of bacterial plasmids in E. coli. Since their impact appears to be plasmid type-dependent, BSRCs are unlikely to be applicable as broad inhibitors of antibiotic resistance propagation.
Collapse
Affiliation(s)
- Rebekah P Nash
- Department of Chemistry, Kenan Laboratories, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3290, USA.
| | | | | | | | | |
Collapse
|
13
|
Baquero F, Coque TM, de la Cruz F. Ecology and evolution as targets: the need for novel eco-evo drugs and strategies to fight antibiotic resistance. Antimicrob Agents Chemother 2011; 55:3649-60. [PMID: 21576439 PMCID: PMC3147629 DOI: 10.1128/aac.00013-11] [Citation(s) in RCA: 123] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In recent years, the explosive spread of antibiotic resistance determinants among pathogenic, commensal, and environmental bacteria has reached a global dimension. Classical measures trying to contain or slow locally the progress of antibiotic resistance in patients on the basis of better antibiotic prescribing policies have clearly become insufficient at the global level. Urgent measures are needed to directly confront the processes influencing antibiotic resistance pollution in the microbiosphere. Recent interdisciplinary research indicates that new eco-evo drugs and strategies, which take ecology and evolution into account, have a promising role in resistance prevention, decontamination, and the eventual restoration of antibiotic susceptibility. This minireview summarizes what is known and what should be further investigated to find drugs and strategies aiming to counteract the "four P's," penetration, promiscuity, plasticity, and persistence of rapidly spreading bacterial clones, mobile genetic elements, or resistance genes. The term "drug" is used in this eco-evo perspective as a tool to fight resistance that is able to prevent, cure, or decrease potential damage caused by antibiotic resistance, not necessarily only at the individual level (the patient) but also at the ecological and evolutionary levels. This view offers a wealth of research opportunities for science and technology and also represents a large adaptive challenge for regulatory agencies and public health officers. Eco-evo drugs and interventions constitute a new avenue for research that might influence not only antibiotic resistance but the maintenance of a healthy interaction between humans and microbial systems in a rapidly changing biosphere.
Collapse
Affiliation(s)
- Fernando Baquero
- Department of Microbiology, Institute Ramón and Cajal for Health Research (IRYCIS), CIBER Research Network in Epidemiology and Public Health (CIBERESP), Ramón y Cajal University Hospital, Madrid, Spain.
| | | | | |
Collapse
|
14
|
Mathers JJ, Flick SC, Cox LA. Longer-duration uses of tetracyclines and penicillins in U.S. food-producing animals: Indications and microbiologic effects. ENVIRONMENT INTERNATIONAL 2011; 37:991-1004. [PMID: 21435723 DOI: 10.1016/j.envint.2011.01.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 01/26/2011] [Accepted: 01/27/2011] [Indexed: 05/12/2023]
Abstract
We review and analyze regulatory categories for longer duration of use (defined as ≥ 7 day) tetracyclines (TCs) and penicillins (PNs) approved for U.S. livestock and poultry, together with scientific studies, surveillance programs and risk assessments pertaining to antimicrobial resistance. Indications listed on a government database were grouped into three broad categories according to the terminology used to describe their use: disease control (C), treatment (T) and growth improvement (G). Consistent with mostly therapeutic uses, the majority (86%) of listed indications had C and/or T terms. Several studies showed interruption of early disease stages in animals and modulation of intestinal microflora. Longer-duration exposures are consistent with bacteriostatic modes of action, where adequate exposure time as well as concentration is needed for sufficient antimicrobial activity. Other effects identified included reduced animal pathogen prevalence, toxin formation, inflammation, environmental impacts, improved animal health, reproductive measures, nutrient utilization, and others. Several animal studies have shown a limited, dose-proportionate, selective increase in resistance prevalence among commensal animal bacteria following longer-duration exposures. Pathogen surveillance programs showed overall stable or declining resistance trends among sentinel bacteria. Quantitative, microbiologically detailed resistance risk assessments indicate small probabilities of human treatment failure due to resistance under current conditions. Evaluations of longer-duration uses of TCs, PNs, and other antimicrobial classes used in food-producing animals should consider mechanisms of activity, known individual- and population-level health and waste reduction effects in addition to resistance risks.
Collapse
|
15
|
|
16
|
Alzeer J, Luedtke NW. pH-Mediated Fluorescence and G-Quadruplex Binding of Amido Phthalocyanines. Biochemistry 2010; 49:4339-48. [DOI: 10.1021/bi9020583] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Jawad Alzeer
- Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, Switzerland 8057
| | - Nathan W. Luedtke
- Institute of Organic Chemistry, University of Zürich, Winterthurerstrasse 190, Switzerland 8057
| |
Collapse
|
17
|
Massey-Gendel E, Zhao A, Boulting G, Kim HY, Balamotis MA, Seligman LM, Nakamoto RK, Bowie JU. Genetic selection system for improving recombinant membrane protein expression in E. coli. Protein Sci 2009; 18:372-83. [PMID: 19165721 DOI: 10.1002/pro.39] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A major barrier to the physical characterization and structure determination of membrane proteins is low yield in recombinant expression. To address this problem, we have designed a selection strategy to isolate mutant strains of Escherichia coli that improve the expression of a targeted membrane protein. In this method, the coding sequence of the membrane protein of interest is fused to a C-terminal selectable marker, so that the production of the selectable marker and survival on selective media is linked to expression of the targeted membrane protein. Thus, mutant strains with improved expression properties can be directly selected. We also introduce a rapid method for curing isolated strains of the plasmids used during the selection process, in which the plasmids are removed by in vivo digestion with the homing endonuclease I-CreI. We tested this selection system on a rhomboid family protein from Mycobacterium tuberculosis (Rv1337) and were able to isolate mutants, which we call EXP strains, with up to 75-fold increased expression. The EXP strains also improve the expression of other membrane proteins that were not the target of selection, in one case roughly 90-fold.
Collapse
|
18
|
Abstract
Biosynthetic studies of aminoglycoside antibiotics have progressed remarkably during the last decade. Many biosynthetic gene clusters for aminoglycoside antibiotics including streptomycin, kanamycin, butirosin, neomycin and gentamicin have been identified to date. In addition, most butirosin and neomycin biosynthetic enzymes have been functionally characterized using recombinant proteins. Herein, we reanalyze biosynthetic genes for structurally related 2-deoxystreptamine (2DOS)-containing aminoglycosides, such as kanamycin, gentamicin and istamycin, based on genetic information including characterized biosynthetic enzymes in neomycin and butirosin biosynthetic pathways. These proposed enzymatic functions for uncharacterized enzymes are expected to support investigation of the complex biosynthetic pathways for this important class of antibiotics.
Collapse
Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, Meguro-ku, Tokyo, Japan
| | | |
Collapse
|
19
|
Christiansen ME, Znosko BM. Thermodynamic characterization of tandem mismatches found in naturally occurring RNA. Nucleic Acids Res 2009; 37:4696-706. [PMID: 19509311 PMCID: PMC2724281 DOI: 10.1093/nar/gkp465] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although all sequence symmetric tandem mismatches and some sequence asymmetric tandem mismatches have been thermodynamically characterized and a model has been proposed to predict the stability of previously unmeasured sequence asymmetric tandem mismatches [Christiansen,M.E. and Znosko,B.M. (2008) Biochemistry, 47, 4329–4336], experimental thermodynamic data for frequently occurring tandem mismatches is lacking. Since experimental data is preferred over a predictive model, the thermodynamic parameters for 25 frequently occurring tandem mismatches were determined. These new experimental values, on average, are 1.0 kcal/mol different from the values predicted for these mismatches using the previous model. The data for the sequence asymmetric tandem mismatches reported here were then combined with the data for 72 sequence asymmetric tandem mismatches that were published previously, and the parameters used to predict the thermodynamics of previously unmeasured sequence asymmetric tandem mismatches were updated. The average absolute difference between the measured values and the values predicted using these updated parameters is 0.5 kcal/mol. This updated model improves the prediction for tandem mismatches that were predicted rather poorly by the previous model. This new experimental data and updated predictive model allow for more accurate calculations of the free energy of RNA duplexes containing tandem mismatches, and, furthermore, should allow for improved prediction of secondary structure from sequence.
Collapse
|
20
|
Aminova O, Paul DJ, Childs-Disney JL, Disney MD. Two-dimensional combinatorial screening identifies specific 6'-acylated kanamycin A- and 6'-acylated neamine-RNA hairpin interactions. Biochemistry 2009; 47:12670-9. [PMID: 18991404 DOI: 10.1021/bi8012615] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Herein, we report the RNA hairpin loops from a six-nucleotide hairpin library that bind 6'-acylated kanamycin A (1) and 6'-acylated neamine (2) identified by two-dimensional combinatorial screening (2DCS). Hairpins selected to bind 1 have K(d)'s ranging from 235 to 1035 nM, with an average K(d) of 618 nM. For 2, the selected hairpins bind with K(d)'s ranging from 135 to 2300 nM, with an average K(d) of 1010 nM. The selected RNA hairpin-ligand interactions are also specific for the ligand that they were selected to bind compared with the other arrayed ligand. For example, the mixture of hairpins selected for 1 on average bind 33-fold more tightly to 1 than to 2, while the mixtures of hairpins selected for 2 on average bind 11-fold more tightly to 2 than to 1. Secondary structure prediction of the selected sequences was completed to determine the motifs that each ligand binds, and the hairpin loop preferences for 1 and 2 were computed. For 1, the preferred hairpin loops contain an adenine separated by at least two nucleotides from a cytosine, for example, ANNCNN (two-tailed p-value = 0.0010) and ANNNCN (two-tailed p-value <0.0001). For 2, the preferred hairpin loops contain both 5'GC and 5'CG steps (two-tailed p-value <0.0001). These results expand the information available on the RNA hairpin loops that bind small molecules and could prove useful for targeting RNA.
Collapse
Affiliation(s)
- Olga Aminova
- Department of Chemistry, University at Buffalo, The State University of New York, and the NYS Center of Excellence in Bioinformatics & Life Sciences, 657 Natural Sciences Complex, Buffalo, New York 14260, USA
| | | | | | | |
Collapse
|
21
|
Abstract
Are plasmids selfish parasitic DNA molecules or an integrated part of the bacterial genome? This chapter reviews the current understanding of the persistence mechanisms of conjugative plasmids harbored by bacterial cells and populations. The diversity and intricacy of mechanisms affecting the successful propagation and long-term continued existence of these extra-chromosomal elements is extensive. Apart from the accessory genetic elements that may provide plasmid-harboring cells a selective advantage, special focus is placed on the mechanisms conjugative plasmids employ to ensure their stable maintenance in the host cell. These importantly include the ability to self-mobilize in a process termed conjugative transfer, which may occur across species barriers. Other plasmid stabilizing mechanisms include the multimer resolution system, active partitioning, and post-segregational-killing of plasmid-free cells. Finally, various molecular adaptations of plasmids to better match the genetic background of their bacterial host cell will be described.
Collapse
|
22
|
Williams JJ, Hergenrother PJ. Exposing plasmids as the Achilles' heel of drug-resistant bacteria. Curr Opin Chem Biol 2008; 12:389-99. [PMID: 18625335 DOI: 10.1016/j.cbpa.2008.06.015] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2008] [Revised: 06/10/2008] [Accepted: 06/16/2008] [Indexed: 10/21/2022]
Abstract
Many multidrug-resistant bacterial pathogens harbor large plasmids that encode proteins conferring resistance to antibiotics. Although the acquisition of these plasmids often enables bacteria to survive in the presence of antibiotics, it is possible that plasmids also represent a vulnerability that can be exploited in tailored antibacterial therapy. This review highlights three recently described strategies designed to specifically combat bacteria harboring such plasmids: inhibition of plasmid conjugation, inhibition of plasmid replication, and exploitation of plasmid-encoded toxin-antitoxin systems.
Collapse
Affiliation(s)
- Julia J Williams
- Department of Microbiology, Roger Adams Laboratory, University of Illinois, Urbana, IL 61801, USA
| | | |
Collapse
|
23
|
Yokoyama K, Yamamoto Y, Kudo F, Eguchi T. Involvement of Two DistinctN-Acetylglucosaminyltransferases and a Dual-Function Deacetylase in Neomycin Biosynthesis. Chembiochem 2008; 9:865-9. [DOI: 10.1002/cbic.200700717] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
24
|
Affiliation(s)
- Jason R Thomas
- Department of Chemistry, Roger Adams Laboratory, University of Illinois, Urbana, Illinois 61822, USA
| | | |
Collapse
|
25
|
Christiansen ME, Znosko BM. Thermodynamic characterization of the complete set of sequence symmetric tandem mismatches in RNA and an improved model for predicting the free energy contribution of sequence asymmetric tandem mismatches. Biochemistry 2008; 47:4329-36. [PMID: 18330995 DOI: 10.1021/bi7020876] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Because of the availability of an abundance of RNA sequence information, the ability to rapidly and accurately predict the secondary structure of RNA from sequence is becoming increasingly important. A common method for predicting RNA secondary structure from sequence is free energy minimization. Therefore, accurate free energy contributions for every RNA secondary structure motif are necessary for accurate secondary structure predictions. Tandem mismatches are prevalent in naturally occurring sequences and are biologically important. A common method for predicting the stability of a sequence asymmetric tandem mismatch relies on the stabilities of the two corresponding sequence symmetric tandem mismatches [Mathews, D. H., Sabina, J., Zuker, M., and Turner, D. H. (1999) J. Mol. Biol. 288, 911-940]. To improve the prediction of sequence asymmetric tandem mismatches, the experimental thermodynamic parameters for the 22 previously unmeasured sequence symmetric tandem mismatches are reported. These new data, however, do not improve prediction of the free energy contributions of sequence asymmetric tandem mismatches. Therefore, a new model, independent of sequence symmetric tandem mismatch free energies, is proposed. This model consists of two penalties to account for destabilizing tandem mismatches, two bonuses to account for stabilizing tandem mismatches, and two penalties to account for A-U and G-U adjacent base pairs. This model improves the prediction of asymmetric tandem mismatch free energy contributions and is likely to improve the prediction of RNA secondary structure from sequence.
Collapse
|
26
|
Childs-Disney JL, Wu M, Pushechnikov A, Aminova O, Disney MD. A small molecule microarray platform to select RNA internal loop-ligand interactions. ACS Chem Biol 2007; 2:745-54. [PMID: 17975888 DOI: 10.1021/cb700174r] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, we report the development of a microarray platform to select RNA motif-ligand interactions that allows simultaneous screening of both RNA and chemical space. We used this platform to identify the RNA internal loops that bind 6'- N-5-hexynoate kanamycin A ( 1). Selected internal loops that bind 1 were studied in detail and commonly display an adenine across from a cytosine independent of the size of the loop. Additional preferences are also observed. For 3 x 3 nucleotide loops, there is a preference for purines, and for 2 x 2 nucleotide loops there is a preference for pyrimidines neighbored by an adenine across from a cytosine. This technique has several advantageous features for selecting RNA motif-ligand interactions: (1) higher affinity RNA motif-ligand interactions are identified by harvesting bound RNAs from lower ligand loadings; (2) bound RNAs are harvested from the array via gel extraction, mitigating kinetic biases in selections; and (3) multiple selections are completed on a single array surface. To further demonstrate that multiple selections can be completed in parallel on the same array surface, we selected the RNA internal loops from a 4096-member RNA internal loop library that bound a four-member aminoglycoside library. These experiments probed 16,384 (4 aminoglycoside x 4096-member RNA library) interactions in a single experiment. These studies allow for parallel screening of both chemical and RNA space to improve our understanding of RNA-ligand interactions. This information may facilitate the rational and modular design of small molecules targeting RNA.
Collapse
Affiliation(s)
- Jessica L. Childs-Disney
- Department of Chemistry and Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, 657 Natural Sciences Complex, Buffalo, New York 14260
| | - Meilan Wu
- Department of Chemistry and Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, 657 Natural Sciences Complex, Buffalo, New York 14260
| | - Alexei Pushechnikov
- Department of Chemistry and Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, 657 Natural Sciences Complex, Buffalo, New York 14260
| | - Olga Aminova
- Department of Chemistry and Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, 657 Natural Sciences Complex, Buffalo, New York 14260
| | - Matthew D. Disney
- Department of Chemistry and Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, 657 Natural Sciences Complex, Buffalo, New York 14260
| |
Collapse
|
27
|
Yokoyama K, Numakura M, Kudo F, Ohmori D, Eguchi T. Characterization and mechanistic study of a radical SAM dehydrogenase in the biosynthesis of butirosin. J Am Chem Soc 2007; 129:15147-55. [PMID: 18001019 DOI: 10.1021/ja072481t] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BtrN encoded in the butirosin biosynthetic gene cluster possesses a CXXXCXXC motif conserved within the radical S-adenosyl methionine (SAM) superfamily. Its gene disruption in the butirosin producer Bacillus circulans caused the interruption of the biosynthetic pathway between 2-deoxy-scyllo-inosamine (DOIA) and 2-deoxystreptamine (DOS). Further, in vitro assay of the overexpressed enzyme revealed that BtrN catalyzed the oxidation of DOIA under the strictly anaerobic conditions along with consumption of an equimolar amount of SAM to produce 5'-deoxyadenosine, methionine, and 3-amino-2,3-dideoxy-scyllo-inosose (amino-DOI). Kinetic analysis showed substrate inhibition by DOIA but not by SAM, which suggests that the reaction is the Ordered Bi Ter mechanism and that SAM is the first substrate and DOIA is the second. The BtrN reaction with [3-2H]DOIA generated nonlabeled, monodeuterated and dideuterated 5'-deoxyadenosines, while no deuterium was incorporated by incubation of nonlabeled DOIA in the deuterium oxide buffer. These results indicated that the hydrogen atom at C-3 of DOIA was directly transferred to 5'-deoxyadenosine to give the radical intermediate of DOIA. Generation of nonlabeled and dideuterated 5'-deoxyadenosines proved the reversibility of the hydrogen abstraction step. The present study suggests that BtrN is an unusual radical SAM dehydrogenase catalyzing the oxidation of the hydroxyl group by a radical mechanism. This is the first report of the mechanistic study on the oxidation of a hydroxyl group by a radical SAM enzyme.
Collapse
Affiliation(s)
- Kenichi Yokoyama
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo152-8551, Japan
| | | | | | | | | |
Collapse
|
28
|
Rule-based modelling of conjugative plasmid transfer and incompatibility. Biosystems 2007; 91:201-15. [PMID: 18023962 DOI: 10.1016/j.biosystems.2007.09.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 08/06/2007] [Accepted: 09/18/2007] [Indexed: 11/23/2022]
Abstract
COSMIC-rules, an individual-based model for bacterial adaptation and evolution, has been used to study virtual transmission of plasmids within bacterial populations, in an environment varying between supportive and inhibitory. The simulations demonstrate spread of antibiotic resistance (R) plasmids, both compatible and incompatible, by the bacterial gene transfer process of conjugation. This paper describes the behaviour of virtual plasmids, their modes of exchange within bacterial populations and the impact of antibiotics, together with the rules governing plasmid transfer. Three case studies are examined: transfer of an R plasmid within an antibiotic-susceptible population, transfer of two incompatible R plasmids and transfer of two compatible R plasmids. R plasmid transfer confers antibiotic resistance on recipients. For incompatible plasmids, one or other plasmid could be maintained in bacterial cells and only that portion of the population acquiring the appropriate plasmid-encoded resistance survives exposure to the antibiotics. By contrast, the compatible plasmids transfer and mix freely within the bacterial population that survives in its entirety in the presence of the antibiotics. These studies are intended to inform models for examining adaptive evolution in bacteria. They provide proof of principle in simple systems as a platform for predicting the behaviour of bacterial populations in more complex situations, for example in response to changing environments or in multi-species bacterial assemblages.
Collapse
|
29
|
Disney MD, Childs-Disney JL. Using selection to identify and chemical microarray to study the RNA internal loops recognized by 6'-N-acylated kanamycin A. Chembiochem 2007; 8:649-56. [PMID: 17394189 DOI: 10.1002/cbic.200600569] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Herein, we describe our initial steps towards identifying the RNA secondary structure motifs that are recognized by small molecules. We selected members of an RNA 3x3 internal loop motif library that bind kanamycin A, an RNA-binding aminoglycoside antibiotic, by using only one round of selection. A small internal-loop library was chosen because members are likely to be present in other larger, biologically relevant RNAs. We have identified several internal loops of various size and base composition that kanamycin A prefers to bind. The highest affinity structures are two 5'-UU/3'-CU 2x2 internal loops closed by AU pairs. Binding is specific for the selected internal loops with the highest affinities, since binding to the RNA cassette used to display the library or to DNA is >150-fold weaker. Enzymatic mapping experiments also confirm binding of kanamycin A to the internal loops. This method lays the foundation for finding RNA secondary structure elements that bind small molecules and for interrogating factors affecting RNA-ligand interactions. Information from these and subsequent studies will: 1) facilitate the rational and modular design of drugs or probes that bind target RNAs with high affinity, provided the secondary structure of the target is known and 2) give insight into the potential bystander RNAs that aminoglycosides bind.
Collapse
Affiliation(s)
- Matthew D Disney
- Department of Chemistry and The New York State Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, 657 Natural Sciences Complex, Buffalo, NY 14260, USA.
| | | |
Collapse
|
30
|
Han Q, Zhao Q, Fish S, Simonsen KB, Vourloumis D, Froelich JM, Wall D, Hermann T. Molecular recognition by glycoside pseudo base pairs and triples in an apramycin-RNA complex. Angew Chem Int Ed Engl 2006; 44:2694-2700. [PMID: 15849690 DOI: 10.1002/anie.200500028] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Qing Han
- Department of Structural Chemistry, Anadys Pharmaceuticals, Inc. 3115 Merryfield Row, San Diego, CA 92121, USA, Fax: (+1) 858-527-1539
| | - Qiang Zhao
- Department of Structural Chemistry, Anadys Pharmaceuticals, Inc. 3115 Merryfield Row, San Diego, CA 92121, USA, Fax: (+1) 858-527-1539
| | - Sarah Fish
- Department of Structural Chemistry, Anadys Pharmaceuticals, Inc. 3115 Merryfield Row, San Diego, CA 92121, USA, Fax: (+1) 858-527-1539
| | - Klaus B Simonsen
- Department of Medicinal Chemistry, Anadys Pharmaceuticals, Inc., USA
- Current address: H. Lundbeck A/S, Copenhagen Valby, Denmark
| | | | | | - Daniel Wall
- Department of Microbiology, Anadys Pharmaceuticals, Inc., USA
| | - Thomas Hermann
- Department of Structural Chemistry, Anadys Pharmaceuticals, Inc. 3115 Merryfield Row, San Diego, CA 92121, USA, Fax: (+1) 858-527-1539
| |
Collapse
|
31
|
Kudo F, Yamamoto Y, Yokoyama K, Eguchi T, Kakinuma K. Biosynthesis of 2-Deoxystreptamine by Three Crucial Enzymes in Streptomyces fradiae NBRC 12773. J Antibiot (Tokyo) 2005; 58:766-74. [PMID: 16506694 DOI: 10.1038/ja.2005.104] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
NeoA, B, and C encoded in the neomycin biosynthetic gene cluster have been enzymatically confirmed to be responsible to the formation of 2-deoxystreptamine (DOS) in Streptomyces fradiae. NeoC was functionally characterized as 2-deoxy-scyllo-inosose synthase, which catalyzes the carbocycle formation from D-glucose-6-phosphate to 2-deoxy-scyllo-inosose. Further, NeoA appeared to catalyze the oxidation of 2-deoxy-scyllo-inosamine (DOIA) with NAD(P)+ forming 3-amino-2,3-dideoxy-scyllo-inosose (amino-DOI). Consequently, NeoA was characterized as 2-deoxy-scyllo-inosamine dehydrogenase. Finally, amino-DOI produced by NeoA from DOIA was transformed into DOS by NeoB. Since NeoB (Neo6) was also reported to be L-glutamine:2-deoxy-scyllo-inosose aminotransferase, all the enzymes in the DOS biosynthesis were characterized for the first time.
Collapse
Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | | | | | | | | |
Collapse
|
32
|
Han Q, Zhao Q, Fish S, Simonsen KB, Vourloumis D, Froelich JM, Wall D, Hermann T. Molecular Recognition by Glycoside Pseudo Base Pairs and Triples in an Apramycin-RNA Complex. Angew Chem Int Ed Engl 2005. [DOI: 10.1002/ange.200500028] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
33
|
|
34
|
DeNap JCB, Hergenrother PJ. Bacterial death comes full circle: targeting plasmid replication in drug-resistant bacteria. Org Biomol Chem 2005; 3:959-66. [PMID: 15750634 DOI: 10.1039/b500182j] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It is now common for bacterial infections to resist the preferred antibiotic treatment. In particular, hospital-acquired infections that are refractory to multiple antibiotics and ultimately result in death of the patient are prevalent. Many of the bacteria causing these infections have become resistant to antibiotics through the process of lateral gene transfer, with the newly acquired genes encoding a variety of resistance-mediating proteins. These foreign genes often enter the bacteria on plasmids, which are small, circular, extrachromosomal pieces of DNA. This plasmid-encoded resistance has been observed for virtually all classes of antibiotics and in a wide variety of Gram-positive and Gram-negative organisms; many antibiotics are no longer effective due to such plasmid-encoded resistance. The systematic removal of these resistance-mediating plasmids from the bacteria would re-sensitize bacteria to standard antibiotics. As such, plasmids offer novel targets that have heretofore been unexploited clinically. This Perspective details the role of plasmids in multi-drug resistant bacteria, the mechanisms used by plasmids to control their replication, and the potential for small molecules to disrupt plasmid replication and re-sensitize bacteria to antibiotics. An emphasis is placed on plasmid replication that is mediated by small counter-transcript RNAs, and the "plasmid addiction" systems that employ toxins and antitoxins.
Collapse
Affiliation(s)
- Johna C B DeNap
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | | |
Collapse
|
35
|
In Brief. Nat Rev Drug Discov 2005. [DOI: 10.1038/nrd1616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|