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Biphenyl dioxygenase from an arctic isolate is not cold adapted
Emma R Master1, Nathalie Y R Agar, Leticia Gómez-Gil
1Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
Applied and Environmental Microbiology
|April 22, 2008
Summary
Biphenyl dioxygenase from a cold-loving bacterium shows activity at 4°C, unlike its counterpart from a moderate-temperature bacterium. This psychrotolerant enzyme offers insights into cold-adapted biocatalysis.
Area of Science:
- Biochemistry
- Enzymology
- Microbiology
Background:
- Biphenyl dioxygenases are crucial enzymes for the degradation of aromatic compounds.
- Understanding the activity of these enzymes at different temperatures is important for bioremediation and industrial applications.
- Psychrotolerant microorganisms possess unique enzymes adapted to cold environments.
Purpose of the Study:
- To characterize the biphenyl dioxygenase (BPDO(Cam-1)) from the psychrotolerant bacterium Pseudomonas sp. strain Cam-1.
- To compare the enzymatic activity and stability of BPDO(Cam-1) with a mesophilic enzyme, BPDO(LB400) from Burkholderia xenovorans LB400.
- To determine the optimal temperature range and stability of BPDO(Cam-1).
Main Methods:
- Purification of biphenyl dioxygenase from Pseudomonas sp. strain Cam-1.
- Enzymatic assays to determine the catalytic efficiency (kcat) at low temperatures (4°C).
- Thermal stability assays by measuring half-life at elevated temperatures (57°C).
Main Results:
- BPDO(Cam-1) exhibited significant catalytic activity towards biphenyl at 4°C (kcat = 1.1 ± 0.1 s⁻¹).
- BPDO(LB400) showed no detectable activity at 4°C.
- BPDO(Cam-1) had a shorter half-life at 57°C compared to BPDO(LB400), indicating lower thermal stability at high temperatures.
- BPDO(Cam-1) was identified as a typical Pseudomonas pseudoalcaligenes KF707-type dioxygenase.
Conclusions:
- Psychrotolerant BPDO(Cam-1) is enzymatically active at low temperatures, demonstrating cold adaptation.
- The enzyme's activity profile suggests potential applications in cold environments for biphenyl degradation.
- BPDO(Cam-1) represents a valuable biocatalyst for low-temperature bioremediation and biotechnological processes.
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