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1.
Chem Pharm Bull (Tokyo) ; 72(3): 249-252, 2024.
Article in English | MEDLINE | ID: mdl-38432905

ABSTRACT

Electrochemical enzyme sensors are suitable for simple monitoring methods, for example, as glucose sensors for diabetic patients; however, they have several disadvantages arising from the properties of the enzyme. Therefore, non-enzymatic electrochemical sensors using functional molecules are being developed. In this paper, we report the electrochemical characterization of a new hydroxylamine compound, 7-azabicyclo[2.2.1]heptan-7-ol (ABHOL), and its application to glucose sensing. Although the cyclic voltammogram for the first cycle was unstable, it was reproducible after the second cycle, enabling electrochemical analysis of ethanol and glucose. In the first cycle, ABHOL caused complex reactions, including electrochemical oxidation and comproportionation with the generated oxoammonium ions. The electrochemical probe performance of ABHOL was more efficient than the typical nitroxyl radical compound, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), and had similar efficiency to 9-azabicyclo[3.3.1]nonane N-oxyl (ABNO), which is activated by the bicyclic structure. The results demonstrated the advantages of ABHOL, which can be synthesized from inexpensive materials via simple methods.


Subject(s)
Azabicyclo Compounds , Ethanol , Glucose , Humans , Azabicyclo Compounds/chemistry
2.
Antimicrob Agents Chemother ; 68(4): e0154823, 2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38415988

ABSTRACT

The impact of penicillin-binding protein 3 (PBP3) modifications that may be identified in Escherichia coli was evaluated with respect to susceptibility to ß-lactam/ß-lactamase inhibitor combinations including ceftazidime-avibactam, imipenem-relebactam, meropenem-vaborbactam, aztreonam-avibactam, cefepime-taniborbactam, and to cefiderocol. A large series of E. coli recombinant strains producing broad-spectrum ß-lactamases was evaluated. While imipenem-relebactam showed a similar activity regardless of the PBP3 background, susceptibility to other molecules tested was affected at various levels. This was particularly the case for ceftazidime-avibactam, aztreonam-avibactam, and cefepime-taniborbactam.


Subject(s)
Aztreonam , Borinic Acids , Boronic Acids , Carboxylic Acids , Cefiderocol , Ceftazidime , Aztreonam/pharmacology , Meropenem/pharmacology , Cefepime/pharmacology , Penicillin-Binding Proteins , Escherichia coli , beta-Lactamases/metabolism , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Azabicyclo Compounds/pharmacology , Azabicyclo Compounds/chemistry , Drug Combinations , Imipenem/pharmacology , Imipenem/chemistry , Microbial Sensitivity Tests
3.
Antimicrob Agents Chemother ; 67(10): e0035023, 2023 10 18.
Article in English | MEDLINE | ID: mdl-37750722

ABSTRACT

Klebsiella pneumoniae carbapenemase-2 (KPC-2) presents a clinical threat as this ß-lactamase confers resistance to carbapenems. Recent variants of KPC-2 in clinical isolates contribute to concerning resistance phenotypes. Klebsiella pneumoniae expressing KPC-2 D179Y acquired resistance to the ceftazidime/avibactam combination affecting both the ß-lactam and the ß-lactamase inhibitor yet has lowered minimum inhibitory concentrations for all other ß-lactams tested. Furthermore, Klebsiella pneumoniae expressing the KPC-2 D179N variant also manifested resistance to ceftazidime/avibactam yet retained its ability to confer resistance to carbapenems although significantly reduced. This structural study focuses on the inhibition of KPC-2 D179N by avibactam and relebactam and expands our previous analysis that examined ceftazidime resistance conferred by D179N and D179Y variants. Crystal structures of KPC-2 D179N soaked with avibactam and co-crystallized with relebactam were determined. The complex with avibactam reveals avibactam making several hydrogen bonds, including with the deacylation water held in place by Ω loop. These results could explain why the KPC-2 D179Y variant, which has a disordered Ω loop, has a decreased affinity for avibactam. The relebactam KPC-2 D179N complex revealed a new orientation of the diazabicyclooctane (DBO) intermediate with the scaffold piperidine ring rotated ~150° from the standard DBO orientation. The density shows relebactam to be desulfated and present as an imine-hydrolysis intermediate not previously observed. The tetrahedral imine moiety of relebactam interacts with the deacylation water. The rotated relebactam orientation and deacylation water interaction could potentially contribute to KPC-mediated DBO fragmentation. These results elucidate important differences that could aid in the design of novel ß-lactamase inhibitors.


Subject(s)
Anti-Bacterial Agents , Ceftazidime , Ceftazidime/pharmacology , Anti-Bacterial Agents/pharmacology , Klebsiella pneumoniae/genetics , Water , beta-Lactamases/genetics , beta-Lactamases/chemistry , Bacterial Proteins/genetics , Azabicyclo Compounds/pharmacology , Azabicyclo Compounds/chemistry , beta-Lactamase Inhibitors/pharmacology , Carbapenems , Drug Combinations , Imines , Microbial Sensitivity Tests
4.
J Am Chem Soc ; 144(45): 20947-20954, 2022 11 16.
Article in English | MEDLINE | ID: mdl-36324090

ABSTRACT

The widespread design of covalent drugs has focused on crafting reactive groups of proper electrophilicity and positioning toward targeted amino-acid nucleophiles. We found that environmental electric fields projected onto a reactive chemical bond, an overlooked design element, play essential roles in the covalent inhibition of TEM-1 ß-lactamase by avibactam. Using the vibrational Stark effect, the magnitudes of the electric fields that are exerted by TEM active sites onto avibactam's reactive C═O were measured and demonstrate an electrostatic gating effect that promotes bond formation yet relatively suppresses the reverse dissociation. These results suggest new principles of covalent drug design and off-target site prediction. Unlike shape and electrostatic complementary which address binding constants, electrostatic catalysis drives reaction rates, essential for covalent inhibition, and deepens our understanding of chemical reactivity, selectivity, and stability in complex systems.


Subject(s)
Azabicyclo Compounds , beta-Lactamases , Azabicyclo Compounds/chemistry , beta-Lactamases/metabolism , Catalytic Domain , Static Electricity , beta-Lactamase Inhibitors/pharmacology
5.
Chem Commun (Camb) ; 58(77): 10869-10872, 2022 Sep 27.
Article in English | MEDLINE | ID: mdl-36074791

ABSTRACT

A catalytic asymmetric total synthesis of avibactam and relebactam, two marketed diazabicyclooctane (DBO) ß-lactamase inhibitors (BLIs), has been accomplished. An important feature of this study is the creation of a stereogenic center by using Rh-catalysed asymmetric hydrogenation, affording the crucial α-amino acid ester derivative with high-level enantiocontrol (99% ee). Furthermore, the adoption of flow technologies for the assembly of a majority of intermediates significantly achieves a faster preparation and greater synthetic efficiency than corresponding batch procedures.


Subject(s)
Anti-Bacterial Agents , beta-Lactamase Inhibitors , Amino Acids , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/chemistry , Azabicyclo Compounds/pharmacology , Esters , Microbial Sensitivity Tests , beta-Lactamase Inhibitors/chemistry , beta-Lactamase Inhibitors/pharmacology , beta-Lactamases/chemistry
6.
Molecules ; 27(12)2022 Jun 14.
Article in English | MEDLINE | ID: mdl-35744953

ABSTRACT

Antibacterial resistance towards the ß-lactam (BL) drugs is now ubiquitous, and there is a major global health concern associated with the emergence of new ß-lactamases (BLAs) as the primary cause of resistance. In addition to the development of new antibacterial drugs, ß-lactamase inhibition is an alternative modality that can be implemented to tackle this resistance channel. This strategy has successfully revitalized the efficacy of a number of otherwise obsolete BLs since the discovery of the first ß-lactamase inhibitor (BLI), clavulanic acid. Over the years, ß-lactamase inhibition research has grown, leading to the introduction of new synthetic inhibitors, and a few are currently in clinical trials. Of note, the 1, 6-diazabicyclo [3,2,1]octan-7-one (DBO) scaffold gained the attention of researchers around the world, which finally culminated in the approval of two BLIs, avibactam and relebactam, which can successfully inhibit Ambler class A, C, and D ß-lactamases. Boronic acids have shown promise in coping with Ambler class B ß-lactamases in recent research, in addition to classes A, C, and D with the clinical use of vaborbactam. This review focuses on the further developments in the synthetic strategies using DBO as well as boronic acid derivatives. In addition, various other potential serine- and metallo- ß-lactamases inhibitors that have been developed in last few years are discussed briefly as well. Furthermore, binding interactions of the representative inhibitors have been discussed based on the crystal structure data of inhibitor-enzyme complex, published in the literature.


Subject(s)
Azabicyclo Compounds , beta-Lactamases , Adaptation, Psychological , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/chemistry , Azabicyclo Compounds/pharmacology , Drug Resistance, Bacterial , Microbial Sensitivity Tests , beta-Lactamase Inhibitors/chemistry , beta-Lactamase Inhibitors/pharmacology , beta-Lactamases/chemistry
7.
J Mol Model ; 28(4): 76, 2022 Mar 04.
Article in English | MEDLINE | ID: mdl-35243556

ABSTRACT

Antibiotic-resistant Acinetobacter baumannii, Pseudomonas aeruginosa, Mycobacterium tuberculosis, Staphylococcus aureus, and Enterobacterales infections are serious global health problems, and class A ß-lactamases are one mechanism that leads to antibiotic resistance. QPX7728, relebactam, and enmetazobactam are new ß-lactamase inhibitors to combat ß-lactam resistance. in silico approach was used in the current study to find which of the three inhibitors would be more effective for all class A ß-lactamases and to reveal molecular insights into the differences between their binding energies. The mutations in conserved residues of the active sites of ß-lactamases were defined using BLDB and Clustal Omega. FastME and MMseq2 were used for cluster and phylogeny analysis. 3D protein structure models for ß-lactamases were built using SWISS-MODEL. ERRAT and Galaxy Web Server were used to verify 42 ß-lactamase protein structures. QPX7728, relebactam, and enmetazobactam were docked to ß-lactamases by using AutoDock 4.2. The TEM76-relebactam, CTX-M-81-relebactam, TEM-76-enmetazobactam, and CTX-M-200-enmetazobactam complexes were simulated by molecular dynamics method for 500 ns. Based on molecular docking results, relebactam and QPX7728 were more favorable inhibitors for serine A ß-lactamases. A 2D representation of the interactions between ligands and ß-lactamases showed that S235, hydrogen bonded with TEM-76, might play a role in inhibitor design. A 500-ns MD analysis of complexes indicated that distance from S70, stability in the enzyme active cavity, and high atomic displacement would account for a significant difference in inhibitor binding affinity.


Subject(s)
Azabicyclo Compounds , beta-Lactamases , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Azabicyclo Compounds/chemistry , Azabicyclo Compounds/pharmacology , Borinic Acids , Carboxylic Acids , Microbial Sensitivity Tests , Molecular Docking Simulation , Triazoles , beta-Lactamases/genetics
8.
Chemistry ; 28(16): e202200088, 2022 Mar 16.
Article in English | MEDLINE | ID: mdl-35084786

ABSTRACT

The total enantioselective synthesis of (+)-eucophylline 1 was achieved using as a key-structural motif a chiral piperidinone bearing the natural product all-carbon quaternary stereocenter. The elaboration of the latter is based on two strategies relying on the free-radical carbo-cyanation and sulfonyl-cyanation respectively of enantiopure substituted cyclopropenes and cyclobutenes. Co- or Ni-boride reduction of the nitrile functional group along with the cyclopropane and cyclobutane ring-opening then led to the formation of the chiral piperidinone ring. Further elaboration of the latter into the key 1-azabicyclo[3.3.1]nonane motif followed by its coupling with a 2-cyanoaniline allowed the formation of the tetrahydrobenzo[b][1,8]-naphthyridine skeleton of 1, which was finally accessible in 17 steps and 5.9 % overall yield from 1,1-dibromobutene.


Subject(s)
Azabicyclo Compounds , Cyclobutanes , Azabicyclo Compounds/chemistry , Cyclobutanes/chemistry , Free Radicals , Stereoisomerism
9.
Bioorg Med Chem ; 54: 116560, 2022 01 15.
Article in English | MEDLINE | ID: mdl-34923389
10.
Bioorg Med Chem ; 53: 116533, 2022 01 01.
Article in English | MEDLINE | ID: mdl-34863065

ABSTRACT

Glioblastoma (GBM) is the most aggressive and treatment-refractory malignant adult brain cancer. After standard of care therapy, the overall median survival for GBM is only ∼6 months with a 5-year survival <10%. Although some patients initially respond to the DNA alkylating agent temozolomide (TMZ), unfortunately most patients become resistant to therapy and brain tumors eventually recur. We previously found that knockout of BRG1 or treatment with PFI-3, a small molecule inhibitor of the BRG1 bromodomain, enhances sensitivity of GBM cells to temozolomide in vitro and in vivo GBM animal models. Those results demonstrated that the BRG1 catalytic subunit of the SWI/SNF chromatin remodeling complex appears to play a critical role in regulating TMZ-sensitivity. In the present study we designed and synthesized Structurally Related Analogs of PFI-3 (SRAPs) and tested their bioactivity in vitro. Among of the SRAPs, 9f and 11d show better efficacy than PFI-3 in sensitizing GBM cells to the antiproliferative and cell death inducing effects of temozolomide in vitro, as well as enhancing the inhibitor effect of temozolomide on the growth of subcutaneous GBM tumors.


Subject(s)
Antineoplastic Agents, Alkylating/pharmacology , Azabicyclo Compounds/pharmacology , DNA Helicases/antagonists & inhibitors , Glioblastoma/drug therapy , Nuclear Proteins/antagonists & inhibitors , Pyridines/pharmacology , Temozolomide/pharmacology , Transcription Factors/antagonists & inhibitors , Animals , Antineoplastic Agents, Alkylating/chemistry , Azabicyclo Compounds/chemistry , Cell Death/drug effects , Cell Proliferation/drug effects , DNA Helicases/metabolism , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Female , Glioblastoma/metabolism , Glioblastoma/pathology , Humans , Mice , Mice, Congenic , Mice, Inbred NOD , Molecular Structure , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/metabolism , Neoplasms, Experimental/pathology , Nuclear Proteins/metabolism , Pyridines/chemistry , Structure-Activity Relationship , Temozolomide/chemistry , Transcription Factors/metabolism
11.
Metallomics ; 13(12)2021 12 10.
Article in English | MEDLINE | ID: mdl-34850060

ABSTRACT

Pyclen-dipicolinate chelates proved to be very efficient chelators for the radiolabeling with ß--emitters such as 90Y. In this study, a pyclen-dipicolinate ligand functionalized with additional C12 alkyl chains was synthesized. The radiolabeling with 90Y proved that the addition of saturated carbon chains does not affect the efficiency of the radiolabeling, whereas a notable increase in lipophilicity of the resulting 90Y radiocomplex was observed. As a result, the compound could be extracted in Lipiodol® and encapsulated in biodegrable pegylated poly(malic acid) nanoparticles demonstrating the potential of lipophilic pyclen-dipicolinate derivatives as platforms for the design of radiopharmaceuticals for the treatment of liver or brain cancers by internal radiotherapy.


Subject(s)
Azabicyclo Compounds/chemistry , Radiopharmaceuticals/chemistry , Radiotherapy/methods , Yttrium Radioisotopes/chemistry , Ethiodized Oil/chemistry , Ligands , Picolinic Acids/chemistry
12.
PLoS One ; 16(10): e0258426, 2021.
Article in English | MEDLINE | ID: mdl-34648556

ABSTRACT

Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp) poses a major threat to human health worldwide. Combination therapies of antibiotics with different mechanisms have been recommended in literatures. This study assessed in vitro antibacterial activities and synergistic activities of ceftazidime/avibactam alone and in combinations against KPC-Kp. In total, 70 isolates from 2 hospitals in Beijing were examined in our study. By using the agar dilution method and broth dilution method, we determined the minimum inhibitory concentration (MIC) of candidate antibiotics. Ceftazidime/avibactam demonstrated promising susceptibility against KPC-Kp (97.14%). Synergistic activities testing was achieved by checkerboard method and found ceftazidime/avibactam-amikacin displayed synergism in 90% isolates. Ceftazidime/avibactam-colistin displayed partial synergistic in 43% isolates, and ceftazidime/avibactam-tigecycline displayed indifference in 67% isolates. In time-kill assays, antibiotics at 1-fold MIC were mixed with bacteria at 1 × 105 CFU/ml and Mueller-Hinton broth (MHB). Combinations of ceftazidime/avibactam with amikacin and tigecycline displayed better antibacterial effects than single drug. Ceftazidime/avibactam-colistin combination did not exhibit better effect than single drug. In KPC-Kp infections, susceptibility testing suggested that ceftazidime/avibactam may be considered as first-line choice. However, monotherapy is often inadequate in infection management. Thus, our study revealed that combination therapy including ceftazidime/avibactam colistin and ceftazidime/avibactam tigecycline may benefit than monotherapy in KPC-Kp treatment. Further pharmacokinetic/pharmacodynamic and mutant prevention concentration studies should be performed to optimize multidrug-regimens.


Subject(s)
Amikacin/chemistry , Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/pharmacology , Ceftazidime/pharmacology , Colistin/chemistry , Drug Resistance, Bacterial/drug effects , Klebsiella pneumoniae/drug effects , Tigecycline/chemistry , Anti-Bacterial Agents/chemistry , Azabicyclo Compounds/chemistry , Bacterial Proteins/metabolism , Ceftazidime/chemistry , Drug Combinations , Drug Synergism , Klebsiella pneumoniae/isolation & purification , Klebsiella pneumoniae/metabolism , Microbial Sensitivity Tests , Time Factors , beta-Lactamases/metabolism
13.
Eur J Med Chem ; 223: 113669, 2021 Nov 05.
Article in English | MEDLINE | ID: mdl-34218084

ABSTRACT

Helicobacter pylori is one of the main causal risk factor in the generation of chronic gastritis, gastroduodenal ulcers and gastric carcinoma. Thus, the eradication of H. pylori infection is an important way for preventing and managing the gastric diseases. Multiple-therapy with several antibacterial agents is used for the eradication of H. pylori infections; however the increase of resistance to H. pylori strains has resulted in unsatisfactory eradication and unsuccessful treatment. Furthermore, the combination therapy with high dosing leads to the disruption of intestinal microbial flora and undesired side effects. Therefore, the search for new therapeutic agents with high selectivity against H. pylori is a field of current interest. In recent years, diverse compounds originating from natural sources or synthetic drug design programs were evaluated and tried to optimize for applying against H. pylori. In this review, we have described various classes of anti-H. pylori compounds, their structure-activity relationship studies, and mechanism of actions, which could be useful for the development of new drugs for the treatment of H. pylori infections.


Subject(s)
Anti-Bacterial Agents/pharmacology , Helicobacter pylori/drug effects , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/therapeutic use , Azabicyclo Compounds/chemistry , Azabicyclo Compounds/pharmacology , Azabicyclo Compounds/therapeutic use , Biological Products/chemistry , Biological Products/pharmacology , Biological Products/therapeutic use , Coordination Complexes/chemistry , Coordination Complexes/pharmacology , Coordination Complexes/therapeutic use , Helicobacter Infections/drug therapy , Humans , Hydroxamic Acids/chemistry , Hydroxamic Acids/pharmacology , Hydroxamic Acids/therapeutic use , Structure-Activity Relationship , Sulfonamides/chemistry , Sulfonamides/pharmacology , Sulfonamides/therapeutic use
14.
Microbiol Spectr ; 9(1): e0058521, 2021 09 03.
Article in English | MEDLINE | ID: mdl-34319141

ABSTRACT

Ceftazidime-avibactam (CZA) has emerged as a promising solution to the lack of new antibiotics against Pseudomonas aeruginosa infections. Data from in vitro assays of CZA combinations, however, are scarce. The objective of our study was to perform a time-kill analysis of the effectiveness of CZA alone and in combination with other antibiotics against a collection of extensively drug-resistant (XDR) P. aeruginosa isolates. Twenty-one previously characterized representative XDR P. aeruginosa isolates were selected. Antibiotic susceptibility was tested by broth microdilution, and results were interpreted using CLSI criteria. The time-kill experiments were performed in duplicate for each isolate. Antibiotics were tested at clinically achievable free-drug concentrations. Different treatment options, including CZA alone and combined with amikacin, aztreonam, meropenem, and colistin, were evaluated to identify the most effective combinations. Seven isolates were resistant to CZA (MIC ≥ 16/4 mg/liter), including four metallo-ß-lactamase (MBL)-carrying isolates and two class A carbapenemases. Five of them were resistant or intermediate to aztreonam (MIC ≥ 16 mg/liter). Three isolates were resistant to amikacin (MIC ≥ 64 mg/liter) and one to colistin (MIC ≥ 4 mg/liter). CZA monotherapy had a bactericidal effect in 100% (14/14) of the CZA-susceptible isolates. Combination therapies achieved a greater overall reduction in bacterial load than monotherapy for the CZA-resistant isolates. CZA plus colistin was additive or synergistic in 100% (7/7) of the CZA-resistant isolates, while CZA plus amikacin and CZA plus aztreonam were additive or synergistic in 85%. CZA combined with colistin, amikacin, or aztreonam was more effective than monotherapy against XDR P. aeruginosa isolates. A CZA combination could be useful for treating XDR P. aeruginosa infections, including those caused by CZA-resistant isolates. IMPORTANCE The emergence of resistance to antibiotics is a serious public health problem worldwide and can be a cause of mortality. For this reason, antibiotic treatment is compromised, and we have few therapeutic options to treat infections. The main goal of our study is to search for new treatment options for infections caused by difficult-to-treat resistant germs. Pseudomonas aeruginosa is a Gram-negative bacterium distributed throughout the world with the ability to become resistant to most available antibiotics. Ceftazidime-avibactam (CZA) emerged as a promising solution to the lack of new antibiotics against infections caused by P. aeruginosa strains. This study intended to analyze the effect of CZA alone or in combination with other available antibiotics against P. aeruginosa strains. The combination of CZA with other antibiotics could be more effective than monotherapy against extensively drug-resistant P. aeruginosa strains.


Subject(s)
Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/pharmacology , Ceftazidime/pharmacology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/drug effects , Anti-Bacterial Agents/chemistry , Azabicyclo Compounds/chemistry , Ceftazidime/chemistry , Drug Combinations , Drug Resistance, Multiple, Bacterial , Humans , Kinetics , Microbial Sensitivity Tests , Pseudomonas Infections/drug therapy , Pseudomonas aeruginosa/growth & development
15.
J Comput Aided Mol Des ; 35(9): 943-952, 2021 09.
Article in English | MEDLINE | ID: mdl-34236545

ABSTRACT

Klebsiella pneumoniae carbapenemase (KPC-2) is the most commonly encountered class A ß-lactamase variant worldwide, which confer high-level resistance to most available antibiotics. In this article we address the issue by a combined approach involving molecular dynamics simulations and hybrid quantum mechanics/molecular mechanics calculations. The study contributes to improve the understanding, at molecular level, of the acylation and deacylation stages of avibactam involved in the inhibition of KPC-2. The results show that both mechanisms, acylation and deacylation, the reaction occur via the formation of a tetrahedral intermediate. The formation of this intermediate corresponds to the rate limiting stage. The activation barriers are 19.5 kcal/mol and 23.0 kcal/mol for the acylation and deacylation stages, respectively. The associated rate constants calculated, using the Eyring equation, are 1.2 × 10-1 and 3.9 × 10-4 (s-1). These values allow estimating a value of 3.3 × 10-3 for the inhibition constant, in good agreement with the experimental value.


Subject(s)
Anti-Bacterial Agents/chemistry , Azabicyclo Compounds/chemistry , Klebsiella pneumoniae/enzymology , beta-Lactamase Inhibitors/chemistry , beta-Lactamases/metabolism , Acylation , Amino Acid Sequence , Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/pharmacology , Catalytic Domain , Molecular Dynamics Simulation , Protein Binding , Protein Conformation , Thermodynamics , beta-Lactamase Inhibitors/pharmacology
16.
J Med Chem ; 64(13): 9496-9512, 2021 07 08.
Article in English | MEDLINE | ID: mdl-34143627

ABSTRACT

Coadministration of ß-lactam and ß-lactamase inhibitor (BLI) is one of the well-established therapeutic measures for bacterial infections caused by ß-lactam-resistant Gram-negative bacteria, whereas we have only two options for orally active BLI, clavulanic acid and sulbactam. Furthermore, these BLIs are losing their clinical usefulness because of the spread of new ß-lactamases, including extended-spectrum ß-lactamases (ESBLs) belonging to class A ß-lactamases, class C and D ß-lactamases, and carbapenemases, which are hardly or not inhibited by these classical BLIs. From the viewpoints of medical cost and burden of healthcare personnel, oral therapy offers many advantages. In our search for novel diazabicyclooctane (DBO) BLIs possessing a thio-functional group at the C2 position, we discovered a 2-sulfinyl-DBO derivative (2), which restores the antibacterial activities of an orally available third-generation cephalosporin, ceftibuten (CTB), against various serine ß-lactamase-producing strains including carbapenem-resistant Enterobacteriaceae (CRE). It can be orally absorbed via the ester prodrug modification and exhibits in vivo efficacy in a combination with CTB.


Subject(s)
Anti-Bacterial Agents/pharmacology , Azabicyclo Compounds/pharmacology , Cyclooctanes/pharmacology , Enterobacteriaceae/drug effects , beta-Lactamase Inhibitors/pharmacology , beta-Lactamases/metabolism , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Azabicyclo Compounds/chemical synthesis , Azabicyclo Compounds/chemistry , Cyclooctanes/chemical synthesis , Cyclooctanes/chemistry , Dose-Response Relationship, Drug , Drug Discovery , Enterobacteriaceae/enzymology , Microbial Sensitivity Tests , Molecular Structure , Serine/antagonists & inhibitors , Serine/metabolism , Structure-Activity Relationship , beta-Lactamase Inhibitors/chemical synthesis , beta-Lactamase Inhibitors/chemistry
17.
J Inorg Biochem ; 222: 111498, 2021 09.
Article in English | MEDLINE | ID: mdl-34120095

ABSTRACT

With the goal of generating a (peroxo)tricopper species analogous to the Peroxy Intermediate proposed for multicopper oxidases, solutions of the copper-superoxide complex [K(Krypt)][LCuO2] (L = N,N'-bis(2,6-diisopropylphenyl)-2,6-pyridinedicarboxamide, Krypt = 4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane) were reacted with the dicopper(I) complex [(TPBN)Cu2(MeCN)2][PF6]2 at -70 °C (TPBN = N,N,N',N'-tetrakis-(2-pyridylmethyl)-1,4-diaminobutane). A metastable intermediate formed, which on the basis of UV-vis, EPR, and resonance Raman spectroscopy was proposed to derive from reaction of two equivalents of the copper-superoxide with one equivalent of the dicopper(I) complex to yield a complex with two (peroxo)dicopper moieties rather than the desired (peroxo)tricopper PI model. A similar intermediate formed upon reaction of [K(Krypt)][LCuO2] with [(BPMA)Cu(MeCN)][PF6] (BPMA = N,N-bis(2-pyridylmethyl)-methyl-amine), which contained the same donor set as provided by TPBN. Comparison of resonance Raman data and consideration of structural preferences for LCuX species led to hypothesis of a µ-η1:η2-peroxo structure for both intermediates.


Subject(s)
Coordination Complexes/chemistry , Peroxides/chemistry , Superoxides/chemistry , Azabicyclo Compounds/chemistry , Coordination Complexes/chemical synthesis , Copper/chemistry , Ligands , Molecular Structure , Peroxides/chemical synthesis , Pyridines/chemistry
18.
Angew Chem Int Ed Engl ; 60(33): 17957-17962, 2021 08 09.
Article in English | MEDLINE | ID: mdl-34036708

ABSTRACT

A synthetic approach to the heterodimeric bisindole alkaloid leucophyllidine is disclosed herein. An enantioenriched lactam building block, synthesized through palladium-catalyzed asymmetric allylic alkylation, served as the precursor to both hemispheres. The eburnamonine-derived fragment was synthesized through a Bischler-Napieralski/hydrogenation approach, while the eucophylline-derived fragment was synthesized by Friedländer quinoline synthesis and two sequential C-H functionalization steps. A convergent Stille coupling and phenol-directed hydrogenation united the two monomeric fragments to afford 16'-epi-leucophyllidine in 21 steps from commercial material.


Subject(s)
Azabicyclo Compounds/chemical synthesis , Indole Alkaloids/chemical synthesis , Vinca Alkaloids/chemical synthesis , Azabicyclo Compounds/chemistry , Indole Alkaloids/chemistry , Molecular Structure , Stereoisomerism , Vinca Alkaloids/chemistry
19.
Inorg Chem ; 60(6): 3604-3619, 2021 Mar 15.
Article in English | MEDLINE | ID: mdl-33625836

ABSTRACT

Magnetic resonance imaging (MRI) has a leading place in medicine as an imaging tool of high resolution for anatomical studies and diagnosis of diseases, in particular for soft tissues that cannot be accessible by other modalities. Many research works are thus focused on improving the images obtained with MRI. This technique has indeed poor sensitivity, which can be compensated by using a contrast agent (CA). Today, the clinically approved CAs on market are solely based on gadolinium complexes that may induce nephrogenic systemic fibrosis for patients with kidney failure, whereas more recent studies on healthy rats also showed Gd retention in the brain. Consequently, researchers try to elaborate other types of safer MRI CAs like manganese-based complexes. In this context, the synthesis of Mn2+ complexes of four 12-membered pyridine-containing macrocyclic ligands based on the pyclen core was accomplished and described herein. Then, the properties of these Mn(II) complexes were studied by two relaxometric methods, 17O NMR spectroscopy and 1H NMR dispersion profiles. The time of residence (τM) and the number of water molecules (q) present in the inner sphere of coordination were determined by these two experiments. The efficacy of the pyclen-based Mn(II) complexes as MRI CAs was evaluated by proton relaxometry at a magnetic field intensity of 1.41 T near those of most medical MRI scanners (1.5 T). Both the 17O NMR and the nuclear magnetic relaxation dispersion profiles indicated that the four hexadentate ligands prepared herein left one vacant coordination site to accommodate one water molecule, rapidly exchanging, in around 6 ns. Furthermore, it has been shown that the presence of an additional amide bond formed when the paramagnetic complex is conjugated to a molecule of interest does not alter the inner sphere of coordination of Mn, which remains monohydrated. These complexes exhibit r1 relaxivities, large enough to be used as clinical MRI CAs (1.7-3.4 mM-1·s-1, at 1.41 T and 37 °C).


Subject(s)
Azabicyclo Compounds/chemistry , Contrast Media/chemistry , Coordination Complexes/chemistry , Azabicyclo Compounds/chemical synthesis , Contrast Media/chemical synthesis , Coordination Complexes/chemical synthesis , Ligands , Magnetic Resonance Imaging , Manganese/chemistry , Oxygen Isotopes/chemistry , Proof of Concept Study , Proton Magnetic Resonance Spectroscopy , Water/chemistry
20.
Int J Biol Macromol ; 177: 337-350, 2021 Apr 30.
Article in English | MEDLINE | ID: mdl-33582216

ABSTRACT

This study evaluated the inhibitory potential of various beta-lactamase inhibitors such as mechanism-based inhibitors (MBIs), carbapenems, monobactam, and non-beta-lactam inhibitors against Bla1, a class-A beta-lactamase encoded by Bacillus anthracis. The binding potential of different inhibitors was estimated using competitive kinetic assay, isothermal titration calorimetry, and Biolayer interferometry. We observed that tazobactam has better inhibition among other MBIs with a characteristics inhibition dissociation constant of 0.51 ± 0.13 µM. Avibactam was also identified as good inhibitor with an inhibition efficiency of 0.6 ± 0.04 µM. All the MBIs (KD = 1.90E-04 M, 2.05E-05 M, 3.55E-04 M for clavulanate, sulbactam and tazobactam) showed significantly better binding potential than carbapenems (KD = 1.02E-03 M, 2.74E-03 M, 1.24E-03 M for ertapenem, imipenem and biapenem respectively). Molecular dynamics simulations were carried out using Bla1-inhibitor complexes to understand the dynamics and stability. The minimum inhibitory concentration (MIC) was carried out by taking various substrates and inhibitors, and later it was followed by cell viability assay. Together, our study helps develop a proper understanding of Bla1 beta-lactamase and its interaction with inhibitory molecules. This study would facilitate comprehending the catalytic divergence of beta-lactamases and the newly emergent resistant strains, focusing on the new generation of therapeutics being less prone to antimicrobial resistance.


Subject(s)
Azabicyclo Compounds/chemistry , Bacillus anthracis/enzymology , Bacterial Proteins , beta-Lactam Resistance , beta-Lactamase Inhibitors/chemistry , beta-Lactamases/chemistry , Bacterial Proteins/antagonists & inhibitors , Bacterial Proteins/chemistry
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