1
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Yu M, Zhao Y. Spectinomycin resistance in Lysobacter enzymogenes is due to its rRNA target but also relies on cell-wall recycling and purine biosynthesis. Front Microbiol 2022; 13:988110. [PMID: 36118211 PMCID: PMC9471086 DOI: 10.3389/fmicb.2022.988110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/05/2022] [Indexed: 11/13/2022] Open
Abstract
Resistance to spectinomycin emerged after widely used for treatment of gonorrhea. Previous studies revealed that Lysobacter enzymogenes strain C3 (LeC3) exhibited elevated level of intrinsic resistance to spectinomycin. In this study, we screened a Tn5 transposon mutant library of LeC3 to elucidate the underlying molecular mechanisms of spectinomycin resistance. Insertion sites in 15 out of 19 mutants recovered with decreased spectinomycin resistance were located on two ribosomal RNA operons at different loci, indicating the pivotal role of ribosomal RNAs in conferring spectinomycin resistance in L. enzymogenes. The other mutants harbored mutations in the tuf, rpoD, mltB, and purB genes. Among them, the tuf and rpoD genes, respectively, encode a translation elongation factor Tu and an RNA polymerase primary sigma factor. They both contribute to protein biosynthesis, where ribosomal RNAs play essential roles. The mltB gene, whose product is involved in cell-wall recycling, was not only associated with resistance against spectinomycin, but also conferred resistance to osmotic stress and ampicillin. In addition, mutation of the purB gene, for which its product is involved in the biosynthesis of inosine and adenosine monophosphates, led to decreased spectinomycin resistance. Addition of exogenous adenine at lower concentration in medium restored the growth deficiency in the purB mutant and increased bacterial resistance to spectinomycin. These results suggest that while cell-wall recycling and purine biosynthesis might contribute to spectinomycin resistance, target rRNAs play critical role in spectinomycin resistance in L. enzymogenes.
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Affiliation(s)
- Menghao Yu
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Shenzhen Key Laboratory of Synthetic Genomics, Guangdong Provincial Key Laboratory of Synthetic Genomics, Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Youfu Zhao
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Department of Plant Pathology, WSU-IAREC, Prosser, WA, United States
- *Correspondence: Youfu Zhao,
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2
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Pajares-Chamorro N, Hammer ND, Chatzistavrou X. Materials for restoring lost Activity: Old drugs for new bugs. Adv Drug Deliv Rev 2022; 186:114302. [PMID: 35461913 DOI: 10.1016/j.addr.2022.114302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 04/04/2022] [Accepted: 04/12/2022] [Indexed: 11/01/2022]
Abstract
The escalation of bacterial resistance to conventional medical antibiotics is a serious concern worldwide. Improvements to current therapies are urgently needed to address this problem. The synergistic combination of antibiotics with other agents is a strategic solution to combat multi-drug-resistant bacteria. Although these combinations decrease the required high dosages and therefore, reduce the toxicity of both agents without compromising the bactericidal effect, they cannot stop the development of further resistance. Recent studies have shown certain elements restore the ability of antibiotics to destroy bacteria that have acquired resistance to them. Due to these synergistic activities, organic and inorganic molecules have been investigated with the goal of restoring antibiotics in new approaches that mitigate the risk of expanding resistance. Herein, we summarize recent studies that restore antibiotics once thought to be ineffective, but have returned to our armamentarium through innovative, combinatorial efforts. A special focus is placed on the mechanisms that allow the synergistic combinations to combat bacteria. The promising data that demonstrated restoration of antimicrobials, supports the notion to find more combinations that can combat antibiotic-resistant bacteria.
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3
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Structural and molecular rationale for the diversification of resistance mediated by the Antibiotic_NAT family. Commun Biol 2022; 5:263. [PMID: 35338238 PMCID: PMC8956665 DOI: 10.1038/s42003-022-03219-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/23/2022] [Indexed: 11/08/2022] Open
Abstract
The environmental microbiome harbors a vast repertoire of antibiotic resistance genes (ARGs) which can serve as evolutionary predecessors for ARGs found in pathogenic bacteria, or can be directly mobilized to pathogens in the presence of selection pressures. Thus, ARGs from benign environmental bacteria are an important resource for understanding clinically relevant resistance. Here, we conduct a comprehensive functional analysis of the Antibiotic_NAT family of aminoglycoside acetyltransferases. We determined a pan-family antibiogram of 21 Antibiotic_NAT enzymes, including 8 derived from clinical isolates and 13 from environmental metagenomic samples. We find that environment-derived representatives confer high-level, broad-spectrum resistance, including against the atypical aminoglycoside apramycin, and that a metagenome-derived gene likely is ancestral to an aac(3) gene found in clinical isolates. Through crystallographic analysis, we rationalize the molecular basis for diversification of substrate specificity across the family. This work provides critical data on the molecular mechanism underpinning resistance to established and emergent aminoglycoside antibiotics and broadens our understanding of ARGs in the environment.
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4
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Kumar P, Agarwal PK, Waddell MB, Mittag T, Serpersu EH, Cuneo MJ. Low‐Barrier and Canonical Hydrogen Bonds Modulate Activity and Specificity of a Catalytic Triad. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201908535] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Prashasti Kumar
- Graduate School of Genome Science and Technology University of Tennessee Knoxville TN 37996 USA
- Present address: Department of Pharmacological Sciences Icahn School of Medicine at Mount Sinai New York NY 10029 USA
| | - Pratul K. Agarwal
- Department of Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN 37996 USA
| | - M. Brett Waddell
- Molecular Interaction Analysis Shared Resource St. Jude Children's Research Hospital Memphis TN 38105 USA
| | - Tanja Mittag
- Department of Structural Biology St. Jude Children's Research Hospital Memphis TN 38105 USA
| | - Engin H. Serpersu
- Department of Biochemistry and Cellular and Molecular Biology University of Tennessee Knoxville TN 37996 USA
- National Science Foundation Alexandria VA 22314 USA
| | - Matthew J. Cuneo
- Department of Structural Biology St. Jude Children's Research Hospital Memphis TN 38105 USA
- Oak Ridge National Laboratory Oak Ridge TN 37830 USA
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5
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Kumar P, Agarwal PK, Waddell MB, Mittag T, Serpersu EH, Cuneo MJ. Low-Barrier and Canonical Hydrogen Bonds Modulate Activity and Specificity of a Catalytic Triad. Angew Chem Int Ed Engl 2019; 58:16260-16266. [PMID: 31515870 DOI: 10.1002/anie.201908535] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/11/2019] [Indexed: 01/14/2023]
Abstract
The position, bonding and dynamics of hydrogen atoms in the catalytic centers of proteins are essential for catalysis. The role of short hydrogen bonds in catalysis has remained highly debated and led to establishment of several distinctive geometrical arrangements of hydrogen atoms vis-à-vis the heavier donor and acceptor counterparts, that is, low-barrier, single-well or short canonical hydrogen bonds. Here we demonstrate how the position of a hydrogen atom in the catalytic triad of an aminoglycoside inactivating enzyme leads to a thirty-fold increase in catalytic turnover. A low-barrier hydrogen bond is present in the enzyme active site for the substrates that are turned over the best, whereas a canonical hydrogen bond is found with the least preferred substrate. This is the first comparison of these hydrogen bonds involving an identical catalytic network, while directly demonstrating how active site electrostatics adapt to the electronic nature of substrates to tune catalysis.
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Affiliation(s)
- Prashasti Kumar
- Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN, 37996, USA.,Present address: Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Pratul K Agarwal
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - M Brett Waddell
- Molecular Interaction Analysis Shared Resource, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Tanja Mittag
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Engin H Serpersu
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, 37996, USA.,National Science Foundation, Alexandria, VA, 22314, USA
| | - Matthew J Cuneo
- Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, TN, 38105, USA.,Oak Ridge National Laboratory, Oak Ridge, TN, 37830, USA
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6
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Yang Y, Feye KM, Shi Z, Pavlidis HO, Kogut M, J Ashworth A, Ricke SC. A Historical Review on Antibiotic Resistance of Foodborne Campylobacter. Front Microbiol 2019; 10:1509. [PMID: 31402900 PMCID: PMC6676416 DOI: 10.3389/fmicb.2019.01509] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 06/17/2019] [Indexed: 01/06/2023] Open
Abstract
Campylobacter is one of the most commonly reported foodborne human bacterial gastrointestinal pathogens. Campylobacter is the etiological agent of campylobacteriosis, which is generally a self-limited illness and therefore does not require treatment. However, when patients are immunocompromised or have other co-morbidities, antimicrobial treatment may be necessary for clinical treatment of campylobacteriosis, macrolides and fluoroquinolones are the drugs of choices. However, the increase in antimicrobial resistance of Campylobacter to clinically important antibiotics may become insurmountable. Because of the transmission between poultry and humans, the poultry industry must now allocate resources to address the problem by reducing Campylobacter as well as antimicrobial use, which may reduce resistance. This review will focus on the incidence of antibiotic-resistant Campylobacter in poultry, the clinical consequences of this resistance, and the mechanisms of antibiotic resistance associated with Campylobacter.
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Affiliation(s)
- Yichao Yang
- Department of Poultry Science, University of Arkansas Fayetteville, Fayetteville, AR, United States
| | - Kristina M Feye
- Southern Plains Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, College Station, TX, United States
| | - Zhaohao Shi
- Center of Food Safety, Department of Food Science, University of Arkansas, Fayetteville, AR, United States
| | | | - Michael Kogut
- Southern Plains Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, College Station, TX, United States
| | - Amanda J Ashworth
- Poultry Production and Product Safety Research Unit (USDA-ARS), Fayetteville, AR, United States
| | - Steven C Ricke
- Southern Plains Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, College Station, TX, United States
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7
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Gozi KS, Froes JR, Deus Ajude LPT, da Silva CR, Baptista RS, Peiró JR, Marinho M, Mendes LCN, Nogueira MCL, Casella T. Dissemination of Multidrug-Resistant Commensal Escherichia coli in Feedlot Lambs in Southeastern Brazil. Front Microbiol 2019; 10:1394. [PMID: 31293542 PMCID: PMC6603138 DOI: 10.3389/fmicb.2019.01394] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 06/04/2019] [Indexed: 12/31/2022] Open
Abstract
Antimicrobial resistance (AR) is a public health issue since it limits the choices to treat infections by Escherichia coli in humans and animals. In Brazil, the ovine meat market has grown in recent years, but studies about AR in sheep are still scarce. Thus, this study aims to investigate the presence of AR in E. coli isolated from lambs during feedlot. To this end, feces from 112 lambs with 2 months of age, after weaning, were collected on the first day of the animals in the feedlot (day 0), and on the last day before slaughtering (day 42). Isolates were selected in MacConkey agar supplemented with 4 mg/L of ceftiofur and identified by biochemical methods. Isolates were submitted to an antimicrobial susceptibility test by disc-diffusion and PCR to investigate genes for phylogenetic group, virulence determinants and resistance to the several antimicrobial classes tested. The genetic localization of the bla genes detected was elucidated by S1-PFGE followed by Southern blot-hybridizations. The isolates were typed by XbaI-PFGE and MLST methods. Seventy-eight E. coli were isolated from 8/112 (7.1%) animals on day 0, and from 55/112 (49.1%) animals on day 42. Since only fimH was present in almost all E. coli (97.4%) as a virulence gene, and also 88.5% belonged to phylogroups B1 or A, we consider that isolates represent intestinal commensal bacteria. The dendrogram separated the 78 non-virulent isolates in seven clusters, two of which comprised 50 E. coli belonging to ST/CC 1727/446 or ST 3994 recovered on day 42 commonly harboring the genotype bla CMY -2-aac(3)-IIa -tetA-sul1-sul2-floR-cmlA. Special attention should be given to the presence of bla CTX-M-15, a worldwide gene spread, and bla CTX-M-14, a hitherto undetected gene in Enterobacteriaceae from food-producing animals in Brazil. Importantly, E. coli lineages and plasmids carrying bla genes detected here have already been reported as sources of infection in humans either from animals, food, or the environment, which raises public health concerns. Hence, two types of commensal E. coli carrying important AR genes clearly prevailed during feedlot, but lambs are also reservoirs of bacteria carrying important AR genes such as bla CTX-M-14 and bla CTX-M-15, mostly related to antimicrobial treatment failure.
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Affiliation(s)
- Katia Suemi Gozi
- Centro de Investigação e Microrganismos, FAMERP, São José do Rio Preto, Brazil
| | | | | | | | | | - Juliana Regina Peiró
- Faculdade de Medicina Veterinária, São Paulo State University (UNESP), Araçatuba, Brazil
| | - Marcia Marinho
- Faculdade de Medicina Veterinária, São Paulo State University (UNESP), Araçatuba, Brazil
| | | | | | - Tiago Casella
- Centro de Investigação e Microrganismos, FAMERP, São José do Rio Preto, Brazil
- Hospital de Base, São José do Rio Preto, Brazil
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8
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Kumar P, Selvaraj B, Serpersu EH, Cuneo MJ. Encoding of Promiscuity in an Aminoglycoside Acetyltransferase. J Med Chem 2018; 61:10218-10227. [PMID: 30347146 DOI: 10.1021/acs.jmedchem.8b01393] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aminoglycoside antibiotics are a large family of antibiotics that can be divided into two distinct classes on the basis of the substitution pattern of the central deoxystreptamine ring. Although aminoglycosides are chemically, structurally, and topologically diverse, some aminoglycoside-modifying enzymes (AGMEs) are able to inactivate as many as 15 aminoglycosides from the two main classes, the kanamycin- and neomycin-based antibiotics. Here, we present the crystal structure of a promiscuous AGME, aminoglycoside- N3-acetyltransferase-IIIb (AAC-IIIb), in the apo form, in binary drug (sisomicin, neomycin, and paromomycin) and coenzyme A (CoASH) complexes, and in the ternary neomycin-CoASH complex. These data provide a structural framework for interpretation of the thermodynamics of enzyme-ligand interactions and the role of solvent in the recognition of ligands. In combination with the recent structure of an AGME that does not have broad substrate specificity, these structures allow for the direct determination of how antibiotic promiscuity is encoded in some AGMEs.
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Affiliation(s)
- Prashasti Kumar
- Graduate School of Genome Science and Technology , The University of Tennessee and Oak Ridge National Laboratory , 1414 West Cumberland Avenue , Knoxville , Tennessee 37996 , United States
| | - Brinda Selvaraj
- Neutron Sciences Directorate , Oak Ridge National Laboratory , Oak Ridge , Tennessee 37831 , United States
| | - Engin H Serpersu
- Graduate School of Genome Science and Technology , The University of Tennessee and Oak Ridge National Laboratory , 1414 West Cumberland Avenue , Knoxville , Tennessee 37996 , United States.,National Science Foundation , 2415 Eisenhower Avenue , Alexandria , Virginia 22314 , United States.,Department of Biochemistry and Cellular and Molecular Biology , The University of Tennessee , 1414 West Cumberland Avenue , Knoxville , Tennessee 37996 , United States
| | - Matthew J Cuneo
- Department of Structural Biology , St. Jude Children's Research Hospital , 262 Danny Thomas Place , Memphis , Tennessee 38105 , United States
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9
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Kumar P, Serpersu EH, Cuneo MJ. A low-barrier hydrogen bond mediates antibiotic resistance in a noncanonical catalytic triad. SCIENCE ADVANCES 2018; 4:eaas8667. [PMID: 29632894 PMCID: PMC5884680 DOI: 10.1126/sciadv.aas8667] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Accepted: 02/20/2018] [Indexed: 05/16/2023]
Abstract
One group of enzymes that confer resistance to aminoglycoside antibiotics through covalent modification belongs to the GCN5-related N-acetyltransferase (GNAT) superfamily. We show how a unique GNAT subfamily member uses a previously unidentified noncanonical catalytic triad, consisting of a glutamic acid, a histidine, and the antibiotic substrate itself, which acts as a nucleophile and attacks the acetyl donor molecule. Neutron diffraction studies allow for unambiguous identification of a low-barrier hydrogen bond, predicted in canonical catalytic triads to increase basicity of the histidine. This work highlights the role of this unique catalytic triad in mediating antibiotic resistance while providing new insights into the design of the next generation of aminoglycosides.
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Affiliation(s)
- Prashasti Kumar
- University of Tennessee–Oak Ridge National Laboratory Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
| | - Engin H. Serpersu
- University of Tennessee–Oak Ridge National Laboratory Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA
- National Science Foundation, 2415 Eisenhower Avenue, Alexandria, VA 22314, USA
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, USA
- Corresponding author. (E.H.S.); (M.J.C.)
| | - Matthew J. Cuneo
- Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
- Corresponding author. (E.H.S.); (M.J.C.)
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10
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Zárate SG, Claure MLDLC, Benito-Arenas R, Revuelta J, Santana AG, Bastida A. Overcoming Aminoglycoside Enzymatic Resistance: Design of Novel Antibiotics and Inhibitors. Molecules 2018; 23:molecules23020284. [PMID: 29385736 PMCID: PMC6017855 DOI: 10.3390/molecules23020284] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/12/2018] [Accepted: 01/26/2018] [Indexed: 11/17/2022] Open
Abstract
Resistance to aminoglycoside antibiotics has had a profound impact on clinical practice. Despite their powerful bactericidal activity, aminoglycosides were one of the first groups of antibiotics to meet the challenge of resistance. The most prevalent source of clinically relevant resistance against these therapeutics is conferred by the enzymatic modification of the antibiotic. Therefore, a deeper knowledge of the aminoglycoside-modifying enzymes and their interactions with the antibiotics and solvent is of paramount importance in order to facilitate the design of more effective and potent inhibitors and/or novel semisynthetic aminoglycosides that are not susceptible to modifying enzymes.
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Affiliation(s)
- Sandra G. Zárate
- Facultad de Tecnología-Carrera de Ingeniería Química, Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca, Regimiento Campos 180, Casilla 60-B, Sucre, Bolivia;
| | - M. Luisa De la Cruz Claure
- Facultad de Ciencias Químico Farmacéuticas y Bioquímicas, Universidad Mayor Real y Pontificia de San Francisco Xavier de Chuquisaca, Dalence 51, Casilla 497, Sucre, Bolivia;
| | - Raúl Benito-Arenas
- Departmento de Química Bio-Orgánica, Instituto de Química Orgánica General (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain; (R.B.-A.); (J.R.)
| | - Julia Revuelta
- Departmento de Química Bio-Orgánica, Instituto de Química Orgánica General (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain; (R.B.-A.); (J.R.)
| | - Andrés G. Santana
- Departmento de Química Bio-Orgánica, Instituto de Química Orgánica General (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain; (R.B.-A.); (J.R.)
- Correspondence: (A.G.S.); (A.B.); Tel: +34-915-612-800 (A.B.)
| | - Agatha Bastida
- Departmento de Química Bio-Orgánica, Instituto de Química Orgánica General (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain; (R.B.-A.); (J.R.)
- Correspondence: (A.G.S.); (A.B.); Tel: +34-915-612-800 (A.B.)
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11
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Bacot-Davis VR, Bassenden AV, Sprules T, Berghuis AM. Effect of solvent and protein dynamics in ligand recognition and inhibition of aminoglycoside adenyltransferase 2″-Ia. Protein Sci 2017; 26:1852-1863. [PMID: 28734024 DOI: 10.1002/pro.3224] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/24/2017] [Accepted: 07/03/2017] [Indexed: 01/15/2023]
Abstract
The aminoglycoside modifying enzyme (AME) ANT(2″)-Ia is a significant target for next generation antibiotic development. Structural studies of a related aminoglycoside-modifying enzyme, ANT(3″)(9), revealed this enzyme contains dynamic, disordered, and well-defined segments that modulate thermodynamically before and after antibiotic binding. Characterizing these structural dynamics is critical for in situ screening, design, and development of contemporary antibiotics that can be implemented in a clinical setting to treat potentially lethal, antibiotic resistant, human infections. Here, the first NMR structural ensembles of ANT(2″)-Ia are presented, and suggest that ATP-aminoglycoside binding repositions the nucleotidyltransferase (NT) and C-terminal domains for catalysis to efficiently occur. Residues involved in ligand recognition were assessed by site-directed mutagenesis. In vitro activity assays indicate a critical role for I129 toward aminoglycoside modification in addition to known catalytic D44, D46, and D48 residues. These observations support previous claims that ANT aminoglycoside sub-class promiscuity is not solely due to binding cleft size, or inherent partial disorder, but can be controlled by ligand modulation on distinct dynamic and thermodynamic properties of ANTs under cellular conditions. Hydrophobic interactions in the substrate binding cleft, as well as solution dynamics in the C-terminal tail of ANT(2″)-Ia, advocate toward design of kanamycin-derived cationic lipid aminoglycoside analogs, some of which have already shown antimicrobial activity in vivo against kanamycin and gentamicin-resistant P. aeruginosa. This data will drive additional in silico, next generation antibiotic development for future human use to combat increasingly prevalent antimicrobial resistance.
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Affiliation(s)
- Valjean R Bacot-Davis
- McGill University, Biochemistry, 3649 Promenade Sir William Osler Room 470, Montreal, QC H3A 0G4, Canada
| | - Angelia V Bassenden
- McGill University, Biochemistry, 3649 Promenade Sir William Osler Room 470, Montreal, QC H3A 0G4, Canada
| | - Tara Sprules
- McGill University, Biochemistry, 3649 Promenade Sir William Osler Room 470, Montreal, QC H3A 0G4, Canada.,Quebec/Eastern Canada NMR Centre, Pulp & Paper Research Centre, 3420 University St. Room 023, Montreal, QC H3A 2A7, Canada
| | - Albert M Berghuis
- McGill University, Biochemistry, 3649 Promenade Sir William Osler Room 470, Montreal, QC H3A 0G4, Canada
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12
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Aboalroub AA, Bachman AB, Zhang Z, Keramisanou D, Merkler DJ, Gelis I. Acetyl group coordinated progression through the catalytic cycle of an arylalkylamine N-acetyltransferase. PLoS One 2017; 12:e0177270. [PMID: 28486510 PMCID: PMC5423648 DOI: 10.1371/journal.pone.0177270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 04/25/2017] [Indexed: 11/18/2022] Open
Abstract
The transfer of an acetyl group from acetyl-CoA to an acceptor amine is a ubiquitous biochemical transformation catalyzed by Gcn5-related N-acetyltransferases (GNATs). Although it is established that the reaction proceeds through a sequential ordered mechanism, the role of the acetyl group in driving the ordered formation of binary and ternary complexes remains elusive. Herein, we show that CoA and acetyl-CoA alter the conformation of the substrate binding site of an arylalkylamine N-acetyltransferase (AANAT) to facilitate interaction with acceptor substrates. However, it is the presence of the acetyl group within the catalytic funnel that triggers high affinity binding. Acetyl group occupancy is relayed through a conserved salt bridge between the P-loop and the acceptor binding site, and is manifested as differential dynamics in the CoA and acetyl-CoA-bound states. The capacity of the acetyl group carried by an acceptor to promote its tight binding even in the absence of CoA, but also its mutually exclusive position to the acetyl group of acetyl-CoA underscore its importance in coordinating the progression of the catalytic cycle.
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Affiliation(s)
- Adam A. Aboalroub
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Ashleigh B. Bachman
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Ziming Zhang
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Dimitra Keramisanou
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - David J. Merkler
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
| | - Ioannis Gelis
- Department of Chemistry, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
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13
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Aboalroub AA, Zhang Z, Keramisanou D, Gelis I. Backbone resonance assignment of an insect arylalkylamine N-acetyltransferase from Bombyx mori reveals conformational heterogeneity. BIOMOLECULAR NMR ASSIGNMENTS 2017; 11:105-109. [PMID: 28236225 DOI: 10.1007/s12104-017-9729-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/16/2017] [Indexed: 06/06/2023]
Abstract
Arylalkylamine N-acetyltransferases (AANATs) catalyze the transfer of an acetyl group from the acetyl-group donor, acetyl-CoA, to an arylalkylamine acceptor. Although a single AANAT has been identified in mammals, insects utilize multiple AANATs in a diverse array of biological processes. AANATs belong to the GCN5-related acetyltransferase (GNAT) superfamily of enzymes, which despite their overall very low sequence homology, are characterized by a well conserved catalytic core domain. The structural properties of many GNATs have been extensively studied by X-ray crystallography that revealed common features during the catalytic cycle. Here we report the 1H, 13C and 15N backbone NMR resonance assignment of the 24 kDa AANAT3 from Bombyx mori (bmAANAT3) as a first step towards understanding the role of protein dynamics in the catalytic properties of AANATs. Our preliminary solution NMR studies reveal that bmAANAT3 is well-folded in solution. The P-loop, which is responsible for cofactor binding, is flexible in the free-state, while a large region of the enzyme interconverts between two distinct conformations in the slow exchange regime.
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Affiliation(s)
- Adam A Aboalroub
- Chemistry Department, University of South Florida, Tampa, FL, 33620, USA
| | - Ziming Zhang
- Chemistry Department, University of South Florida, Tampa, FL, 33620, USA
| | | | - Ioannis Gelis
- Chemistry Department, University of South Florida, Tampa, FL, 33620, USA.
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Kumar P, Serpersu EH. Thermodynamics of an aminoglycoside modifying enzyme with low substrate promiscuity: The aminoglycoside N3 acetyltransferase-VIa. Proteins 2017; 85:1258-1265. [PMID: 28316100 DOI: 10.1002/prot.25286] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 11/07/2022]
Abstract
Kinetic, thermodynamic, and structural properties of the aminoglycoside N3-acetyltransferase-VIa (AAC-VIa) are determined. Among the aminoglycoside N3-acetyltransferases, AAC-VIa has one of the most limited substrate profiles. Kinetic studies showed that only five aminoglycosides are substrates for this enzyme with a range of fourfold difference in kcat values. Larger differences in KM (∼40-fold) resulted in ∼30-fold variation in kcat /KM . Binding of aminoglycosides to AAC-VIa was enthalpically favored and entropically disfavored with a net result of favorable Gibbs energy (ΔG < 0). A net deprotonation of the enzyme, ligand, or both accompanied the formation of binary and ternary complexes. This is opposite of what was observed with several other aminoglycoside N3-acetyltransferases, where ligand binding causes more protonation. The change in heat capacity (ΔCp) was different in H2 O and D2 O for the binary enzyme-sisomicin complex but remained the same in both solvents for the ternary enzyme-CoASH-sisomicin complex. Unlike, most other aminoglycoside-modifying enzymes, the values of ΔCp were within the expected range of protein-carbohydrate interactions. Solution behavior of AAC-VIa was also different from the more promiscuous aminoglycoside N3-acetyltransferases and showed a monomer-dimer equilibrium as detected by analytical ultracentrifugation (AUC). Binding of ligands shifted the enzyme to monomeric state. Data also showed that polar interactions were the most dominant factor in dimer formation. Overall, thermodynamics of ligand-protein interactions and differences in protein behavior in solution provide few clues on the limited substrate profile of this enzyme despite its >55% sequence similarity to the highly promiscuous aminoglycoside N3-acetyltransferase. Proteins 2017; 85:1258-1265. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Prashasti Kumar
- Graduate School of Genome Science and Technology, The University of Tennessee and Oak Ridge National Laboratory, Knoxville, Tennessee, 37996
| | - Engin H Serpersu
- Graduate School of Genome Science and Technology, The University of Tennessee and Oak Ridge National Laboratory, Knoxville, Tennessee, 37996
- Department of Biochemistry, Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee, 37996
- National Science Foundation, Arlington, Virgina 22230
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Abstract
Antibiotic-resistant bacteria that are difficult or impossible to treat are becoming increasingly common and are causing a global health crisis. Antibiotic resistance is encoded by several genes, many of which can transfer between bacteria. New resistance mechanisms are constantly being described, and new genes and vectors of transmission are identified on a regular basis. This article reviews recent advances in our understanding of the mechanisms by which bacteria are either intrinsically resistant or acquire resistance to antibiotics, including the prevention of access to drug targets, changes in the structure and protection of antibiotic targets and the direct modification or inactivation of antibiotics.
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Jing X, Serpersu EH. Solvent Reorganization Plays a Temperature-Dependent Role in Antibiotic Selection by a Thermostable Aminoglycoside Nucleotidyltransferase-4′. Biochemistry 2014; 53:5544-50. [DOI: 10.1021/bi5006283] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaomin Jing
- Department
of Biochemistry and Cellular and Molecular Biology, The University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Engin H. Serpersu
- Graduate
School of Genome Science and Technology, The University of Tennessee and Oak Ridge National Laboratories, Knoxville, Tennessee 37996, United States
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