| Item type: | Article | ||||
|---|---|---|---|---|---|
| Journal or Publication Title: | ACS Catalysis | ||||
| Publisher: | AMER CHEMICAL SOC | ||||
| Place of Publication: | WASHINGTON | ||||
| Volume: | 13 | ||||
| Number of Issue or Book Chapter: | 23 | ||||
| Page Range: | pp. 15558-15571 | ||||
| Date: | 2023 | ||||
| Institutions: | Biology, Preclinical Medicine > Institut für Biophysik und physikalische Biochemie > Prof. Dr. Reinhard Sterner | ||||
| Identification Number: |
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| Keywords: | SP STRAIN ADP; PSEUDOMONAS SP; AMIDOHYDROLASE SUPERFAMILY; ATRAZINE CATABOLISM; CYANURIC ACID; METAL CENTER; BIODEGRADATION; PROMISCUITY; SEQUENCE; GENES; anthropogenic compound; atrazine; AtzB; enzyme evolution; herbicide; promiscuousactivity; protein engineering; xenobiotics | ||||
| Dewey Decimal Classification: | 500 Science > 540 Chemistry & allied sciences 500 Science > 570 Life sciences | ||||
| Status: | Published | ||||
| Refereed: | Yes, this version has been refereed | ||||
| Created at the University of Regensburg: | Yes | ||||
| Item ID: | 75622 |
Abstract
The mechanisms underlying the rapid evolution of novel enzymatic activities from promiscuous side activities are poorly understood. Recently emerged enzymes catalyzing the catabolic degradation of xenobiotic substances that have been spread out into the environment during the last few decades provide an exquisite opportunity to study these mechanisms. A prominent example is the herbicide atrazine ...
Abstract
The mechanisms underlying the rapid evolution of novel enzymatic activities from promiscuous side activities are poorly understood. Recently emerged enzymes catalyzing the catabolic degradation of xenobiotic substances that have been spread out into the environment during the last few decades provide an exquisite opportunity to study these mechanisms. A prominent example is the herbicide atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine), which is degraded through a number of enzymatic reactions, constituting the Atz pathway. Here, we analyzed the evolution of hydroxyatrazine ethylaminohydrolase AtzB, a Zn(II)-dependent metalloenzyme that adopts the amidohydrolase fold and catalyzes the second step of the Atz pathway. We searched for promiscuous side activities of AtzB, which might point to the identity of its progenitor. These investigations revealed that AtzB has a low promiscuous guanine deaminase activity. Furthermore, we found that the two closest AtzB homologues, which have not been functionally annotated until now, are guanine deaminases with modest promiscuous hydroxyatrazine hydrolase activity. Based on sequence comparisons with the closest AtzB homologues, the guanine deaminase activity of AtzB could be increased by three orders of magnitude through the introduction of only four active site mutations. Interestingly, introducing the four inverse mutations into the AtzB homologues significantly enhanced their hydroxyatrazine hydrolase activity and, in one case, is even equivalent to that of wild-type AtzB. Molecular dynamics simulations elucidated the structural and molecular basis for the mutation-induced activity changes. The example of AtzB highlights how novel enzymes with high catalytic proficiency can evolve from low promiscuous side activities by only a few mutational events within a short period of time.
Metadata last modified: 18 Mar 2025 10:02
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