Faculty Collaboration Database

Swit_4259, an acetoacetate decarboxylase-like enzyme from Sphingomonas wittichii RW1. Acta Crystallogr F Struct Biol Commun 2017 Dec 01;73(Pt 12):672-681

Date

12/05/2017

Pubmed ID

29199988

Pubmed Central ID

PMC5713672

DOI

10.1107/S2053230X17015862

Scopus ID

2-s2.0-85037072903 (requires institutional sign-in at Scopus site)   2 Citations

Abstract

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.

Author List

Mydy LS, Mashhadi Z, Knight TW, Fenske T, Hagemann T, Hoppe RW, Han L, Miller TR, Schwabacher AW, Silvaggi NR

Author

Nicholas R. Silvaggi PhD Assistant Professor in the Chemistry and Biochemistry department at University of Wisconsin - Milwaukee

MESH terms used to index this publication - Major topics in bold

Acetoacetates
Bacterial Proteins
Carboxy-Lyases
Catalytic Domain
Crystallography, X-Ray
Ketoglutaric Acids
Magnetic Resonance Spectroscopy
Models, Molecular
Protein Conformation
Pyruvic Acid
Spectrometry, Mass, Electrospray Ionization
Sphingomonas
Substrate Specificity