An additional ionic bond suggested by molecular modelling of TEM-2 might induce a slight discrepancy between catalytic properties of TEM-1 and TEM-2 β-lactamases

The structural bases of antibiotic resistance in the clinically derived mutant beta-lactamases TEM-30, TEM-32, and TEM-34.

Widespread use of beta-lactam antibiotics has promoted the evolution of beta-lactamase mutant enzymes that can hydrolyze ever newer classes of these drugs. Among the most pernicious mutants are the inhibitor-resistant TEM beta-lactamases (IRTs), which elude mechanism-based inhibitors, such as clavulanate. Despite much research on these IRTs, little is known about the structural bases of their a...

Analytical Tem Characterisation of Catalytic Materials

The application of analytical transmission electron microscopy in characterisations of catalytic materials is presented by studying the mechanically activated vanadium pentoxide V2O5. Local morphology and lattice distortion are studied by TEM while the oxidation states are determined by EELS. The mechanical activation can be described as a two -stage process: crushing of large crystals into sma...

Evolution of TEM-type enzymes: biochemical and genetic characterization of two new complex mutant TEM enzymes, TEM-151 and TEM-152, from a single patient.

Two clinical isolates of Escherichia coli, CF1179 and CF1295, were isolated from a patient hospitalized in the hematology unit of the University Hospital of Clermont-Ferrand, Clermont-Ferrand, France. They were resistant to penicillin-clavulanate combinations and to ceftazidime. The double-disk synergy test was positive only for isolate CF1179. Molecular comparison of the isolates showed that t...

Mutual influence of secondary and key drug‐resistance mutations on catalytic properties and thermal stability of TEM‐type β‐lactamases

Highly mutable β-lactamases are responsible for the ability of Gram-negative bacteria to resist β-lactam antibiotics. Using site-directed mutagenesis technique, we have produced in vitro a number of recombinant analogs of naturally occurring TEM-type β-lactamases, bearing the secondary substitution Q39K and key mutations related to the extended-spectrum (E104K, R164S) and inhibitor-resistant (M...

Etymologia: TEM