Swit_4259, an acetoacetate decarboxylase-like enzyme from Sphingomonas wittichii RW1
| Autor: | T. William Knight, Zahra Mashhadi, Alan W. Schwabacher, Robert W. Hoppe, Hagemann Trevor, Lisa S. Mydy, Todd R. Miller, Tyler Grant Fenske, Lanlan Han, Nicholas R. Silvaggi |
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| Rok vydání: | 2017 |
| Předmět: |
Models
Molecular 0301 basic medicine Spectrometry Mass Electrospray Ionization Magnetic Resonance Spectroscopy Carboxy-Lyases Protein Conformation Stereochemistry 030106 microbiology Biophysics Acetoacetate decarboxylase activity Context (language use) Crystallography X-Ray Sphingomonas Biochemistry Acetoacetates Substrate Specificity Research Communications 03 medical and health sciences Bacterial Proteins Acetoacetate decarboxylase Structural Biology Catalytic Domain Pyruvic Acid Genetics biology Chemistry Active site Condensed Matter Physics Lyase biology.organism_classification Enzyme structure Dehydratase Sphingomonas wittichii biology.protein Ketoglutaric Acids |
| Zdroj: | Acta Crystallographica Section F Structural Biology Communications. 73:672-681 |
| ISSN: | 2053-230X |
| Popis: | The Gram-negative bacterium Sphingomonas wittichii RW1 is notable for its ability to metabolize a variety of aromatic hydrocarbons. Not surprisingly, the S. wittichii genome contains a number of putative aromatic hydrocarbon-degrading gene clusters. One of these includes an enzyme of unknown function, Swit_4259, which belongs to the acetoacetate decarboxylase-like superfamily (ADCSF). Here, it is reported that Swit_4259 is a small (28.8 kDa) tetrameric ADCSF enzyme that, unlike the prototypical members of the superfamily, does not have acetoacetate decarboxylase activity. Structural characterization shows that the tertiary structure of Swit_4259 is nearly identical to that of the true decarboxylases, but there are important differences in the fine structure of the Swit_4259 active site that lead to a divergence in function. In addition, it is shown that while it is a poor substrate, Swit_4259 can catalyze the hydration of 2-oxo-hex-3-enedioate to yield 2-oxo-4-hydroxyhexanedioate. It is also demonstrated that Swit_4259 has pyruvate aldolase-dehydratase activity, a feature that is common to all of the family V ADCSF enzymes studied to date. The enzymatic activity, together with the genomic context, suggests that Swit_4259 may be a hydratase with a role in the metabolism of an as-yet-unknown hydrocarbon. These data have implications for engineering bioremediation pathways to degrade specific pollutants, as well as structure–function relationships within the ADCSF in general. |
| Databáze: | OpenAIRE |
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