Purification and characterization of the acetone carboxylase of Cupriavidus metallidurans strain CH34 - PubMed (original) (raw)

Purification and characterization of the acetone carboxylase of Cupriavidus metallidurans strain CH34

Caroline Rosier et al. Appl Environ Microbiol. 2012 Jun.

Abstract

Acetone carboxylase (Acx) is a key enzyme involved in the biodegradation of acetone by bacteria. Except for the Helicobacteraceae family, genome analyses revealed that bacteria that possess an Acx, such as Cupriavidus metallidurans strain CH34, are associated with soil. The Acx of CH34 forms the heterohexameric complex α(2)β(2)γ(2) and can carboxylate only acetone and 2-butanone in an ATP-dependent reaction to acetoacetate and 3-keto-2-methylbutyrate, respectively.

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Figures

Fig 1

Acetone carboxylase expression. SDS-PAGE of protein extracts (10 μg) from CH34 grown in the presence of 9 mM gluconate (1), 25 mM acetone (2), 25 mM isopropanol (3), and 25 mM _n_-propanol (4). (5) Protein extract (10 μg) from the acxR knockout mutant cultivated in the presence of acetone 25 mM. (6) Purified acetone carboxylase (5 μg). Molecular mass is indicated on the left.

Fig 2

Comparison of the acetone and acetophenone carboxylases from various species. 1, information obtained from reference ; 2, information obtained from references and ; 3, information obtained from reference ; 4, information obtained from reference ; 5, information obtained from reference . A superscript “a” indicates that the products of the enzymatic reaction were not identified in X. autotrophicus and R. capsulatus; for A. aromaticum, the nature of the product was suggested by the authors but not experimentally identified. A superscript “b” indicates that the product of the enzymatic reaction was not identified. ND, not determined. +, supports the Acx reaction at different levels; −, does not support the Acx reaction.

Fig 3

Determination by NMR analyses of acetone carboxylase reaction products with 2-butanone as the substrate. (A and B) Enzymatic reactions realized without substrates. (C, D, E, and F) Enzymatic reactions realized in the presence of 81.5 μg of pure Acx with 8 mM, 12 mM, 16 mM, and 24 mM ATP, respectively. (G) Enzymatic reaction realized with 16 mM ATP and 163 μg of pure Acx. ppm, parts per million.

References

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Purification and characterization of the acetone carboxylase of Cupriavidus metallidurans strain CH34 - PubMed (original) (raw)