Substitutions of Thr-103-Ile and Trp-138-Gly in Amidase from Pseudomonas aeruginosa Are Responsible for Altered Kinetic Properties and Enzyme Instability

2001 ◽  
Vol 17 (3) ◽  
pp. 201-212 ◽  
Author(s):  
Amin Karmali ◽  
Rita Pacheco ◽  
Renée Tata ◽  
Paul Brown
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Kinetic Properties

scholarly journals BEL-2, an Extended-Spectrum β-Lactamase with Increased Activity toward Expanded-Spectrum Cephalosporins in Pseudomonas aeruginosa

2009 ◽  
Vol 54 (1) ◽  
pp. 533-535 ◽  
Author(s):  
Laurent Poirel ◽  
Jean-Denis Docquier ◽  
Filomena De Luca ◽  
Annemie Verlinde ◽  
Louis Ide ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Kinetic Properties ◽  
Extended Spectrum ◽  
Positive Isolate ◽  
Increased Activity

ABSTRACT A Pseudomonas aeruginosa isolate recovered in Belgium produced a novel extended-spectrum ß-lactamase, BEL-2, differing from BEL-1 by a single Leu162Phe substitution. That modification significantly altered the kinetic properties of the enzyme, increasing its affinity for expanded-spectrum cephalosporins. The bla BEL-2 gene was identified from a P. aeruginosa isolate clonally related to another bla BEL-1-positive isolate.

scholarly journals Genetic and biochemical characterization of the Na + /H + antiporters of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Sara Foreman ◽  
Kristina Ferrara ◽  
Teri Hreha ◽  
Ana Duran-Pinedo ◽  
Jorge Frias-Lopez ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biochemical Characterization ◽  
Physiological Role ◽  
Glycerol Metabolism ◽  
Kinetic Properties ◽  
Wild Type ◽  
Wide Range ◽  
Quadruple Mutant

Pseudomonas aeruginosa has four Na + /H + antiporters that interconvert and balance Na + and H + gradients across the membrane. These gradients are important for bioenergetics and ionic homeostasis. To understand these transporters, we have constructed four strains, each of which has only one antiporter: NhaB, NhaP, NhaP2, and Mrp. We also constructed a quadruple deletion mutant that has no Na + /H + antiporters. Although the antiporters of P. aeruginosa have previously been studied, the strains constructed here present the opportunity to characterize their kinetic properties in their native membranes and their roles in the physiology of P. aeruginosa . The strains expressing only NhaB or Mrp, the two electrogenic antiporters, are able to grow essentially as the wild type across a range of [Na + ] and pH. Strains with only NhaP or NhaP2, which are electroneutral, grow more poorly at increasing [Na + ], especially at high pH, with NhaP the most sensitive. The strain with no Na + /H + antiporters is extremely sensitive to [Na + ] and shows essentially no Na + (Li + )/H + antiporter activity but retains most K + /H + antiporter activity of the wild type at pH 7.5 and approximately half at pH 8.5. We also used the four strains that each express one of the four antiporters to characterize the kinetic properties of each transporter. RNA-seq analysis of the quadruple deletion strain showed widespread changes, including pyocyanin synthesis, biofilm formation, and nitrate and glycerol metabolism. Thus, the strains constructed for this study will open a new door to understanding the physiological role of these proteins and their activities in P. aeruginosa . Importance Pseudomonas aeruginosa has four Na + /H + antiporters that connect and interconvert its Na + and H + gradients. We have constructed four deletion mutants, each of which has only one of the four Na + /H + antiporters. These strains made it possible to study the properties and physiological roles of each antiporter independently in its native membrane. Mrp and NhaB are each able to sustain growth over a wide range of pH and [Na + ], whereas the two electroneutral antiporters, NhaP and NhaP2, are most effective at low pH. We also constructed a quadruple mutant, lacking all four antiporters in which the H + and Na + gradients are disconnected. This will make it possible to study the role of the two gradients independently.

Characterization of arylsulfatase isoenzymes from Pseudomonas aeruginosa

1972 ◽  
Vol 18 (5) ◽  
pp. 561-568 ◽  
Author(s):  
G. J. Delisle ◽  
F. H. Milazzo
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Kinetic Properties ◽  
Type I ◽  
Similar Kinetic ◽  
Substrate Hydrolysis ◽  
Curious Property

A method is described for the separation and isolation of two electrophoretically distinct arylsulfatases (arylsulfatase EC.3.1.6.1) from Pseudomonas aeruginosa.Characterization of the enzymes revealed that they were type I arylsulfatases, with similar kinetic properties. They differed, however, in respect to charge, pH optima for substrate hydrolysis, and activation by anions. In addition, the enzymes displayed dual pH optima curves with both substrates used and the curious property of a shift in pH optima with varied p-nitrophenyl sulfate concentrations.

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