scholarly journals Structural Insights into the Inhibition of the Extended-Spectrum β-Lactamase PER-2 by Avibactam

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Melina Ruggiero ◽  
Krisztina M. Papp-Wallace ◽  
Florencia Brunetti ◽  
Melissa D. Barnes ◽  
Robert A. Bonomo ◽  
...  
Keyword(s):  
Side Chain ◽  
Structural Studies ◽  
Content Type ◽  
Class A ◽  
Extended Spectrum ◽  
Inhibition Constants ◽  
The Rich ◽  
Structural Insights ◽  
Insight Into ◽  
Made In

ABSTRACT The diazabicyclooctane (DBO) avibactam (AVI) reversibly inactivates most serine-β-lactamases. Previous investigations showed that inhibition constants of AVI toward class A PER-2 are reminiscent of values observed for class C and D β-lactamases (i.e., k2/K of ≈103 M−1 s−1) but lower than other class A β-lactamases (i.e., k2/K = 104 to 105 M−1 s−1). Herein, biochemical and structural studies were conducted with PER-2 and AVI to explore these differences. Furthermore, biochemical studies on Arg220 and Thr237 variants with AVI were conducted to gain deeper insight into the mechanism of PER-2 inactivation. The main biochemical and structural observations revealed the following: (i) both amino-acid substitutions in Arg220 and the rich hydrophobic content in the active site hinder the binding of catalytic waters and acylation, impairing AVI inhibition; (ii) movement of Ser130 upon binding of AVI favors the formation of a hydrogen bond with the sulfate group of AVI; and (iii) the Thr237Ala substitution alters the AVI inhibition constants. The acylation constant (k2/K) of PER-2 by AVI is primarily influenced by stabilizing hydrogen bonds involving AVI and important residues such as Thr237 and Arg220. (Variants in Arg220 demonstrate a dramatic reduction in k2/K.) We also observed that displacement of Ser130 side chain impairs AVI acylation, an observation not made in other extended-spectrum β-lactamases (ESBLs). Comparatively, relebactam combined with a β-lactam is more potent against Escherichia coli producing PER-2 variants than β-lactam–AVI combinations. Our findings provide a rationale for evaluating the utility of the currently available DBO inhibitors against unique ESBLs like PER-2 and anticipate the effectiveness of these inhibitors toward variants that may eventually be selected upon AVI usage.

scholarly journals Structural Insights into the TLA-3 Extended-Spectrum β-Lactamase and Its Inhibition by Avibactam and OP0595

2017 ◽  
Vol 61 (10) ◽  
Author(s):  
Wanchun Jin ◽  
Jun-ichi Wachino ◽  
Yoshihiro Yamaguchi ◽  
Kouji Kimura ◽  
Anupriya Kumar ◽  
...  
Keyword(s):  
Rate Constant ◽  
Catalytic Efficiency ◽  
Amino Acid Residues ◽  
Inhibitory Effects ◽  
Content Type ◽  
Class A ◽  
Extended Spectrum ◽  
Structural Template ◽  
Structural Insights ◽  
Positively Charged

ABSTRACT The development of effective inhibitors that block extended-spectrum β-lactamases (ESBLs) and restore the action of β-lactams represents an effective strategy against ESBL-producing Enterobacteriaceae. We evaluated the inhibitory effects of the diazabicyclooctanes avibactam and OP0595 against TLA-3, an ESBL that we identified previously. Avibactam and OP0595 inhibited TLA-3 with apparent inhibitor constants (Ki app) of 1.71 ± 0.10 and 1.49 ± 0.05 μM, respectively, and could restore susceptibility to cephalosporins in the TLA-3-producing Escherichia coli strain. The value of the second-order acylation rate constant (k 2/K, where k 2 is the acylation rate constant and K is the equilibrium constant) of avibactam [(3.25 ± 0.03) × 103 M−1 · s−1] was closer to that of class C and D β-lactamases (k 2/K, <104 M−1 · s−1) than that of class A β-lactamases (k 2/K, >104 M−1 · s−1). In addition, we determined the structure of TLA-3 and that of TLA-3 complexed with avibactam or OP0595 at resolutions of 1.6, 1.6, and 2.0 Å, respectively. TLA-3 contains an inverted Ω loop and an extended loop between the β5 and β6 strands (insertion after Ser237), which appear only in PER-type class A β-lactamases. These structures might favor the accommodation of cephalosporins harboring bulky R1 side chains. TLA-3 presented a high catalytic efficiency (k cat/Km ) against cephalosporins, including cephalothin, cefuroxime, and cefotaxime. Avibactam and OP0595 bound covalently to TLA-3 via the Ser70 residue and made contacts with residues Ser130, Thr235, and Ser237, which are conserved in ESBLs. Additionally, the sulfate group of the inhibitors formed polar contacts with amino acid residues in a positively charged pocket of TLA-3. Our findings provide a structural template for designing improved diazabicyclooctane-based inhibitors that are effective against ESBL-producing Enterobacteriaceae.

scholarly journals Identification of Novel VEB β-Lactamase Enzymes and Their Impact on Avibactam Inhibition

2016 ◽  
Vol 60 (5) ◽  
pp. 3183-3186 ◽  
Author(s):  
Sushmita D. Lahiri ◽  
Richard A. Alm
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Binding Pocket ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Content Type ◽  
Class A ◽  
Extended Spectrum ◽  
Class C

ABSTRACTCeftazidime-avibactam has activity againstPseudomonas aeruginosaandEnterobacteriaceaeexpressing numerous class A and class C β-lactamases, although the ability to inhibit many minor enzyme variants has not been established. Novel VEB class A β-lactamases were identified during characterization of surveillance isolates. The cloned novel VEB β-lactamases possessed an extended-spectrum β-lactamase phenotype and were inhibited by avibactam in a concentration-dependent manner. The residues that comprised the avibactam binding pocket were either identical or functionally conserved. These data demonstrate that avibactam can inhibit VEB β-lactamases.

scholarly journals PME-1, an Extended-Spectrum β-Lactamase Identified in Pseudomonas aeruginosa

2011 ◽  
Vol 55 (6) ◽  
pp. 2710-2713 ◽  
Author(s):  
Guo-Bao Tian ◽  
Jennifer M. Adams-Haduch ◽  
Tatiana Bogdanovich ◽  
Hong-Ning Wang ◽  
Yohei Doi
Keyword(s):  
Pseudomonas Aeruginosa ◽  
United Arab Emirates ◽  
Stenotrophomonas Maltophilia ◽  
Hydrolytic Activity ◽  
The United States ◽  
Amino Acid Identity ◽  
The Novel ◽  
Content Type ◽  
Class A ◽  
Extended Spectrum

ABSTRACTA novel extended-spectrum β-lactamase (ESBL) was identified in aPseudomonas aeruginosaclinical isolate obtained from a patient admitted to a hospital in Pennsylvania in 2008. The patient had a prolonged hospitalization in a hospital in Dubai, United Arab Emirates, before being transferred to the United States. The novel ESBL, designated PME-1 (Pseudomonas aeruginosaESBL 1), is a molecular class A, Bush-Jacoby-Medeiros group 2be enzyme and shared 50, 43, and 41% amino acid identity with the L2 β-lactamase ofStenotrophomonas maltophilia, CTX-M-9, and KPC-2, respectively. PME-1 conferred clinically relevant resistance to ceftazidime, cefotaxime, cefepime, and aztreonam inP. aeruginosaPAO1 but not to carbapenems. Purified PME-1 showed good hydrolytic activity against ceftazidime, cefotaxime, and aztreonam, while activity against carbapenems and cefepime could not be measured. PME-1 was inhibited well by β-lactamase inhibitors, including clavulanic acid, sulbactam, and tazobactam. TheblaPME-1gene was carried by an approximately 9-kb plasmid and flanked by tandem ISCR24elements.

scholarly journals Characterization of CIA-1, an Ambler Class A Extended-Spectrum β-Lactamase from Chryseobacterium indologenes

2011 ◽  
Vol 56 (1) ◽  
pp. 588-590 ◽  
Author(s):  
Takehisa Matsumoto ◽  
Mika Nagata ◽  
Nau Ishimine ◽  
Kenji Kawasaki ◽  
Kazuyoshi Yamauchi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Reference Strain ◽  
Content Type ◽  
Chryseobacterium Indologenes ◽  
Esbl Gene ◽  
Class A ◽  
Extended Spectrum ◽  
Class B ◽  
Lactamase Gene

ABSTRACTAn Ambler class A β-lactamase gene,blaCIA-1, was cloned from the reference strainChryseobacterium indologenesATCC 29897 and expressed inEscherichia coliBL21. TheblaCIA-1gene encodes a novel extended-spectrum β-lactamase (ESBL) that shared 68% and 60% identities with the CGA-1 and CME-1 β-lactamases, respectively.blaCIA-1-like genes were detected from clinical isolates. In addition to the metallo-β-lactamase IND of Ambler class B,C. indologeneshas a class A ESBL gene,blaCIA-1, located on the chromosome.

Emergency preparedness in the hospitality industry in Sri Lanka

2019 ◽  
Vol 10 (2/3) ◽  
pp. 167-174
Author(s):  
Tilanka Chandrasekera ◽  
Paulette Hebert
Keyword(s):  
Sri Lanka ◽  
Emergency Preparedness ◽  
Design Methodology ◽  
Hospitality Industry ◽  
Demographic Information ◽  
Online Questionnaire ◽  
Content Type ◽  
Coastal Belt ◽  
Insight Into ◽  
Made In

Purpose The purpose of this study is to investigate the emergency preparedness of the hospitality industry in Sri Lanka, focusing on hotels and restaurants in the southern coastal belt. Design/methodology/approach A questionnaire on emergency preparedness was provided to 30 randomly recruited participants from the industry. The survey consisted of 30 open and closed-ended questions, focusing on basic demographic information, information about emergency preparedness of the facility, food safety and issues regarding power management. Findings The findings of this study provide insight on the emergency preparedness of the hospitality industry in Sri Lanka. Research limitations/implications In its current iteration, the sample size was a major limitation. The study was conducted by using an online questionnaire, and that affected the number of responses received. Social implications The results provide insight into how improvements can be made in future developments of similar nature especially in terms of emergency mitigation efforts. These findings also provide suggestions on areas that need to be improved through educating the industry. Originality/value This study is a part of a larger project where the research team is investigating emergency preparedness in the hospitality industry in different regions of the world.

scholarly journals Active-Site Protonation States in an Acyl-Enzyme Intermediate of a Class A β-Lactamase with a Monobactam Substrate

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Venu Gopal Vandavasi ◽  
Patricia S. Langan ◽  
Kevin L. Weiss ◽  
Jerry M. Parks ◽  
Jonathan B. Cooper ◽  
...  
Keyword(s):  
Active Site ◽  
Catalytic Mechanism ◽  
Active Site Residues ◽  
Hydrogen Atoms ◽  
Content Type ◽  
X Ray Crystallography ◽  
General Base ◽  
Class A ◽  
Extended Spectrum ◽  
Enzyme Intermediate

ABSTRACT The monobactam antibiotic aztreonam is used to treat cystic fibrosis patients with chronic pulmonary infections colonized by Pseudomonas aeruginosa strains expressing CTX-M extended-spectrum β-lactamases. The protonation states of active-site residues that are responsible for hydrolysis have been determined previously for the apo form of a CTX-M β-lactamase but not for a monobactam acyl-enzyme intermediate. Here we used neutron and high-resolution X-ray crystallography to probe the mechanism by which CTX-M extended-spectrum β-lactamases hydrolyze monobactam antibiotics. In these first reported structures of a class A β-lactamase in an acyl-enzyme complex with aztreonam, we directly observed most of the hydrogen atoms (as deuterium) within the active site. Although Lys 234 is fully protonated in the acyl intermediate, we found that Lys 73 is neutral. These findings are consistent with Lys 73 being able to serve as a general base during the acylation part of the catalytic mechanism, as previously proposed.

scholarly journals mSphere of Influence: Structural Insights into the Molecular Mechanism Underlying Placental Malaria

mSphere ◽  
2021 ◽  
Vol 6 (3) ◽  
Author(s):  
Maria del Pilar Quintana
Keyword(s):  
Plasmodium Falciparum ◽  
Chondroitin Sulfate ◽  
Placental Malaria ◽  
Structural Basis ◽  
Content Type ◽  
Link Type ◽  
Structural Details ◽  
Inhibitory Antibodies ◽  
Structural Insights ◽  
Insight Into

ABSTRACT Maria del Pilar Quintana works on immunology and pathogenesis of severe malaria. In this mSphere of Influence article, she reflects on how the papers “Structural basis for placental malaria mediated by Plasmodium falciparum VAR2CSA” (R. Ma, T. Lian, R. Huang, J. P. Renn, J. D. Petersen, J. Zimmerberg, P. E. Duffy, N. H. Tolia, Nat Microbiol 6:380–391, 2021, https://doi.org/10.1038/s41564-020-00858-9) and “Cryo-EM reveals the architecture of placental malaria VAR2CSA and provides molecular insight into chondroitin sulfate binding” (K. Wang, R. Dagil, T. Lavsten, S. K. Misra, C. B. Spliid, Y. Wang, T. Gustavsson, D. R. Sandoval, E. E. Vidal-Calvo, S. Choudary, M. O. Agerback, K. Lindorff-Larsen, M. A. Nielsen, T. G. Theander, J. S. Sharp, T. M. Clausen, P. Gourdon, A. Salanti [Research Square preprint], 2021, https://doi.org/10.21203/rs.3.rs-121821/v1) shed light on the precise structural details behind Plasmodium falciparum VAR2CSA binding to chondroitin sulfate A (CSA) in the placenta and how these novel insights have changed the way she will approach her work toward the discovery of new broadly cross-reactive/inhibitory antibodies targeting VAR2CSA.

scholarly journals Probing the Mechanism of Inactivation of the FOX-4 Cephamycinase by Avibactam

2018 ◽  
Vol 62 (5) ◽  
pp. e02371-17 ◽  
Author(s):  
Michiyoshi Nukaga ◽  
Krisztina M. Papp-Wallace ◽  
Tyuji Hoshino ◽  
Scott T. Lefurgy ◽  
Christopher R. Bethel ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Single Amino Acid ◽  
Content Type ◽  
Class A ◽  
Hydrogen Bonding Interactions ◽  
Extended Spectrum ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor ◽  
Inhibition Analysis

ABSTRACTCeftazidime-avibactam is a “second-generation” β-lactam–β-lactamase inhibitor combination that is effective againstEnterobacteriaceaeexpressing class A extended-spectrum β-lactamases, class A carbapenemases, and/or class C cephalosporinases. Knowledge of the interactions of avibactam, a diazabicyclooctane with different β-lactamases, is required to anticipate future resistance threats. FOX family β-lactamases possess unique hydrolytic properties with a broadened substrate profile to include cephamycins, partly as a result of an isoleucine at position 346, instead of the conserved asparagine found in most AmpCs. Interestingly, a single amino acid substitution at N346 in theCitrobacterAmpC is implicated in resistance to the aztreonam-avibactam combination. In order to understand how diverse active-site topologies affect avibactam inhibition, we tested a panel of clinicalEnterobacteriaceaeisolates producingblaFOXusing ceftazidime-avibactam, determined the biochemical parameters for inhibition using the FOX-4 variant, and probed the atomic structure of avibactam with FOX-4. Avibactam restored susceptibility to ceftazidime for most isolates producingblaFOX; two isolates, one expressingblaFOX-4and the other producingblaFOX-5, displayed an MIC of 16 μg/ml for the combination. FOX-4 possessed ak2/Kvalue of 1,800 ± 100 M−1· s−1and an off rate (koff) of 0.0013 ± 0.0003 s−1. Mass spectrometry showed that the FOX-4–avibactam complex did not undergo chemical modification for 24 h. Analysis of the crystal structure of FOX-4 with avibactam at a 1.5-Å resolution revealed a unique characteristic of this AmpC β-lactamase. Unlike in thePseudomonas-derived cephalosporinase 1 (PDC-1)–avibactam crystal structure, interactions (e.g., hydrogen bonding) between avibactam and position I346 in FOX-4 are not evident. Furthermore, another residue is not observed to be close enough to compensate for the loss of these critical hydrogen-bonding interactions. This observation supports findings from the inhibition analysis of FOX-4; FOX-4 possessed the highestKd(dissociation constant) value (1,600 nM) for avibactam compared to other AmpCs (7 to 660 nM). Medicinal chemists must consider the properties of extended-spectrum AmpCs, such as the FOX β-lactamases, for the design of future diazabicyclooctanes.

Editorial: the role of the editor – managing fair play

2017 ◽  
Vol 31 (3) ◽  
pp. 201-203 ◽  
Author(s):  
Rebekah Russell-Bennett ◽  
Steve Baron
Keyword(s):  
Design Methodology ◽  
Competitive Environment ◽  
Fair Play ◽  
Editorial Process ◽  
Content Type ◽  
Journal Editors ◽  
Trade Offs ◽  
Insight Into ◽  
Made In

Purpose This editorial aims to highlight the challenges and dilemmas faced by journal editors and the implications for the editorial process. Design/methodology/approach A sporting metaphor has been used. A soccer referee is used to highlight the tasks, roles and dilemmas faced by editors. Findings Editors need to identify the role they wish to play in the editorial process, and this role involves balancing the dilemmas and identifying trade-offs. Originality/value This research offers insight into the editorial role for authors to assist them in understanding both the process and the decisions that are made in a complex, competitive environment of publishing.

scholarly journals Exploring predictive maintenance applications in industry

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Wieger Tiddens ◽  
Jan Braaksma ◽  
Tiedo Tinga
Keyword(s):  
Implementation Process ◽  
Predictive Maintenance ◽  
Content Type ◽  
Maintenance Decisions ◽  
Multiple Case ◽  
Physical Assets ◽  
Insight Into ◽  
Selection Of ◽  
Made In

PurposeAsset owners and maintainers need to make timely and well-informed maintenance decisions based on the actual or predicted condition of their physical assets. However, only few companies have succeeded to implement predictive maintenance (PdM) effectively. Therefore, this paper aims to identify why only few companies were able to successfully implement PdM.Design/methodology/approachA multiple-case study including 13 cases in various industries in The Netherlands was conducted. This paper examined the choices made in practice to achieve PdM and possible dependencies between and motivations for these choices.FindingsAn implementation process for PdM appeared to comprise four elements: a trigger, data collection, maintenance technique (MT) selection and decision-making. For each of these elements, several options were available. By identifying the choices made by companies in practice and mapping them on the proposed elements, logical combinations appeared. These combinations can provide insight into the PdM implementation process and may also lead to guidance on this topic. Further, while successful companies typically combined various techniques, the mostly applied techniques were still those based on previous experiences.Research limitations/implicationsThis research calls for better methods or procedures to guide the selection and use of suitable types of PdM, directed by the firm's ambition level and the available data.Originality/valueWhile it is important for firms to make suitable choices during implementation, the literature often focusses only on developing additional techniques for PdM. This paper provides new insights into the application and selection of techniques for PdM in practice and helps practitioners reduce the often applied trial-and-error process.

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