Detection and characterization of VIM-52, a new variant of VIM-1 from Klebsiella pneumoniae clinical isolate

2021 ◽  
Author(s):  
Marie de Barsy ◽  
Paola Sandra Mercuri ◽  
Saoussen Oueslati ◽  
Eddy Elisée ◽  
Te-Din Huang ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Substrate Specificity ◽  
Clinical Isolate ◽  
Targeted Mutagenesis ◽  
Kinetic Measurements ◽  
Steady State Kinetic ◽  
New Variant ◽  
State Kinetic ◽  
Global Health Problem

Over the last two decades, antimicrobial resistance has become a global health problem. In Gram-negative bacteria, metallo-β-lactamases (MBLs), which inactivate virtually all β-lactams, increasingly contribute to this phenomenon. The aim of this study is to characterize VIM-52, a His224Arg variant of VIM-1, identified in a Klebsiella pneumoniae clinical isolate. VIM-52 conferred lower MICs to cefepime and ceftazidime as compared to VIM-1. These results were confirmed by steady state kinetic measurements, where VIM-52 yielded a lower activity towards ceftazidime and cefepime but not against carbapenems. Residue 224 is part of the L10 loop (residues 221-241), which borders the active site. As Arg 224 and Ser 228 are both playing an important and interrelated role in enzymatic activity, stability and substrate specificity for the MBLs, targeted mutagenesis at both positions were performed and further confirmed their crucial role for substrate specificity.

scholarly journals Characterization of Nicotinamidases: Steady State Kinetic Parameters, Classwide Inhibition by Nicotinaldehydes, and Catalytic Mechanism

Biochemistry ◽  
2010 ◽  
Vol 49 (49) ◽  
pp. 10421-10439 ◽  
Author(s):  
Jarrod B. French ◽  
Yana Cen ◽  
Tracy L. Vrablik ◽  
Ping Xu ◽  
Eleanor Allen ◽  
...  
Keyword(s):  
Steady State ◽  
Kinetic Parameters ◽  
Catalytic Mechanism ◽  
Steady State Kinetic ◽  
State Kinetic

scholarly journals Genomic characterization of a KPC-23-producing Klebsiella pneumoniae ST258 clinical isolate resistant to ceftazidime-avibactam

2019 ◽  
Vol 25 (6) ◽  
pp. 763.e5-763.e8 ◽  
Author(s):  
I. Galani ◽  
A. Antoniadou ◽  
I. Karaiskos ◽  
K. Kontopoulou ◽  
H. Giamarellou ◽  
...  
Keyword(s):  
Klebsiella Pneumoniae ◽  
Clinical Isolate ◽  
Genomic Characterization

scholarly journals Proton-linked l-rhamnose transport, and its comparison with l-fucose transport in Enterobacteriaceae

1993 ◽  
Vol 290 (3) ◽  
pp. 833-842 ◽  
Author(s):  
J A R Muiry ◽  
T C Gunn ◽  
T P McDonald ◽  
S A Bradley ◽  
C G Tate ◽  
...  
Keyword(s):  
Transport System ◽  
Erwinia Carotovora ◽  
Alkaline Ph ◽  
Transport Activity ◽  
Ph Change ◽  
Kinetic Measurements ◽  
E Coli ◽  
Steady State Kinetic ◽  
Competitive Inhibitors ◽  
State Kinetic

1. An alkaline pH change occurred when L-rhamnose, L-mannose or L-lyxose was added to L-rhamnose-grown energy-depleted suspensions of strains of Escherichia coli. This is diagnostic of sugar-H+ symport activity. 2. L-Rhamnose, L-mannose and L-lyxose were inducers of the sugar-H+ symport and of L-[14C]rhamnose transport activity. L-Rhamnose also induced the biochemically and genetically distinct L-fucose-H+ symport activity in strains competent for L-rhamnose metabolism. 3. Steady-state kinetic measurements showed that L-mannose and L-lyxose were competitive inhibitors (alternative substrates) for the L-rhamnose transport system, and that L-galactose and D-arabinose were competitive inhibitors (alternative substrates) for the L-fucose transport system. Additional measurements with other sugars of related structure defined the different substrate specificities of the two transport systems. 4. The relative rates of H+ symport and of sugar metabolism, and the relative values of their kinetic parameters, suggested that the physiological role of the transport activity was primarily for utilization of L-rhamnose, not for L-mannose or L-lyxose. 5. L-Rhamnose transport into subcellular vesicles of E. coli was dependent on respiration, was optimal at pH 7, and was inhibited by protonophores and ionophores. It was insensitive to N-ethylmaleimide or cytochalasin B. 6. L-Rhamnose, L-mannose and L-lyxose each elicited an alkaline pH change when added to energy-depleted suspensions of L-rhamnose-grown Salmonella typhimurium LT2, Klebsiella pneumoniae, Klebsiella aerogenes, Erwinia carotovora carotovora and Erwinia carotovora atroseptica. The relative rates of subsequent acidification varied, depending on both the organism and the sugar. L-Fucose promoted an alkaline pH change in all the L-rhamnose-induced organisms except the Erwinia species. No L-rhamnose-H+ symport occurred in any organism grown on L-fucose. 7. All these results showed that L-rhamnose transport into the micro-organisms occurred by a system different from that for L-fucose transport. Both systems are energized by the trans-membrane electrochemical gradient of protons. 8. Neither steady-state kinetic measurements nor binding-protein assays revealed the existence of a second L-rhamnose transport system in E. coli.

Pre-Steady-State Kinetic Study of Substrate Specificity ofEscherichia coliFormamidopyrimidine−DNA Glycosylase†

Biochemistry ◽  
2007 ◽  
Vol 46 (2) ◽  
pp. 424-435 ◽  
Author(s):  
Nikita A. Kuznetsov ◽  
Vladimir V. Koval ◽  
Dmitry O. Zharkov ◽  
Yuri N. Vorobjev ◽  
Georgy A. Nevinsky ◽  
...  
Keyword(s):  
Steady State ◽  
Substrate Specificity ◽  
Kinetic Study ◽  
Dna Glycosylase ◽  
Steady State Kinetic ◽  
State Kinetic

scholarly journals Dihydrolipoamide dehydrogenase from halophilic archaebacteria

1984 ◽  
Vol 218 (3) ◽  
pp. 811-818 ◽  
Author(s):  
M J Danson ◽  
R Eisenthal ◽  
S Hall ◽  
S R Kessell ◽  
D L Williams
Keyword(s):  
Steady State ◽  
Iodoacetic Acid ◽  
Enzymic Activity ◽  
Evolutionary Significance ◽  
Dihydrolipoamide Dehydrogenase ◽  
Kinetic Measurements ◽  
Steady State Kinetic ◽  
Halophilic Archaebacteria ◽  
Eukaryotic Organisms ◽  
State Kinetic

Dihydrolipoamide dehydrogenase has been discovered in the halophilic archaebacteria for the first time. The enzyme from both classical and alkaliphilic halobacteria has been investigated. (1) The enzyme specifically catalysed the stoichiometric oxidation of dihydrolipoamide by NAD+. Enzymic activity was optimal at 2 M-NaCl and was remarkably resistant to thermal denaturation. (2) The relative molecular masses (Mr) of the native enzyme from the various species of halobacteria were determined to be within the range 112000-120000. (3) The enzyme exhibited a hyperbolic dependence of catalytic activity on both dihydrolipoamide and NAD+ concentrations. From these steady-state kinetic measurements the dissociation constant (Ks) of dihydrolipoamide was determined to be 57 (+/- 5) microM. (4) The enzyme was only susceptible to inactivation by iodoacetic acid in the presence of its reducing ligands, dihydrolipoamide or NADH. The rate of inactivation followed a hyperbolic dependence on the concentration of dihydrolipoamide, from which the Ks of this substrate was calculated to be 55 (+/- 7) microM. Together with the steady-state kinetic data, the pattern of inactivations is consistent with the involvement in catalysis of a reversibly reducible disulphide bond, as has been found in dihydrolipoamide dehydrogenase from non-archaebacterial species. In eubacterial and eukaryotic organisms, dihydrolipoamide dehydrogenase functions in the 2-oxo acid dehydrogenase complexes. These multienzyme systems have not been detected in the archaebacteria, and, in the context of this apparent absence, the possible function and evolutionary significance of archaebacterial dihydrolipoamide dehydrogenase are discussed.

A Kinetic Method for Characterization of Heterogenous Fibrinogen and Its Application to Fibrinogen Grand Rapids, a Congenital Dysfibrinogenemia

1982 ◽  
Vol 48 (02) ◽  
pp. 182-186 ◽  
Author(s):  
D L Higgins ◽  
S D Lewis ◽  
J A Penner ◽  
J A Shafer
Keyword(s):  
Steady State ◽  
Kinetic Parameter ◽  
Kinetic Analysis ◽  
Kinetic Method ◽  
Plasma Fibrinogen ◽  
Normal Value ◽  
Steady State Kinetic ◽  
Grand Rapids ◽  
State Kinetic

SummaryA kinetic analysis was developed to determine the steady state kinetic parameter kcat/KM for the thrombin-catalyzed release of FPA from abnormal and normal fibrinogen in mixtures of the two. Such mixtures are likely to comprise the fibrinogen of individuals with congenital dysfibrinogenemia. The analysis was used to characterize fibrinogen Grand Rapids, a new congenital dysfibrinogenemia. It indicated that fibrinogen from affected individuals was composed of normal and abnormal fibrinogen in roughly equal amounts, and that the value of kcat/KM for the thrombin-catalyzed release of FPA from the fibrinogen variant was 77fold lower than that for the release of FPA from the normal fibrinogen. In separate studies, fibrinogen Grand Rapids was found to exhibit a reduced clottability. Additionally, affected individuals appeared to have plasma fibrinogen concentrations which were about one-third the normal value.

KPC-39-mediated resistance to Ceftazidime-Avibactam in a Klebsiella pneumoniae ST307 clinical isolate

2021 ◽  
Author(s):  
Agnès B. Jousset ◽  
Saoussen Oueslati ◽  
Cécile Emeraud ◽  
Rémy A Bonnin ◽  
Laurent Dortet ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Steady State ◽  
Klebsiella Pneumoniae ◽  
Single Amino Acid ◽  
Healthcare Settings ◽  
Steady State Kinetic ◽  
Amino Acid Variant ◽  
European Healthcare ◽  
Dynamics Simulations ◽  
State Kinetic

Resistance to ceftazidime–avibactam (CAZ-AVI) combination is being increasingly reported. Here, we report a CAZ-AVI resistant Klebsiella pneumoniae belonging to the high-risk ST307 clone and producing KPC-39, a single amino-acid variant of KPC-3 (A172T). Cloning experiments, steady state kinetic parameters and molecular dynamics simulations revealed a loss of carbapenemase activity and an increased affinity for ceftazidime. KPC-39 was identified in a patient without prior exposure to CAZ-AVI, suggesting silent dissemination in European healthcare settings.

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