Proteomic investigation of enzymes involved in 2-ethylhexyl nitrate biodegradation in Mycobacterium austroafricanum IFP 2173.
2-Ethyhexyl nitrate (2-EHN) is a synthetic chemical used as a diesel fuel additive, which is recalcitrant to biodegradation. In this study, the enzymes involved in 2-EHN degradation were investigated in Mycobacterium austroafricanum IFP 2173. Using two-dimensional gel electrophoresis and a shotgun proteomic approach, a total of 398 proteins appeared to be more abundant in cells exposed to 2-EHN than in acetate-grown cells. This set of proteins includes multiple isoenzymes of the beta-oxidation pathway, two alcohol and one aldehyde dehydrogenase, as well as four cytochromes P450, including one CYP153 which functions as an alkane hydroxylase. Strain IFP 2173 was also found to contain two alkB-like genes encoding putative membrane-bound alkane hydroxylases. RT-PCR experiments showed that the gene encoding the CYP153 protein, as well as alkB genes, were expressed on 2-EHN. These findings are discussed in the light of a recently proposed 2-EHN degradation pathway involving an initial attack by an alkane hydroxylase and one turn of beta-oxidation, leading to the accumulation of a gamma-lactone as a dead-end product.
Laboratoire de Chimie et Biologie des Métaux, CEA, iRTSV, 17 Rue des Martyrs, 38054 Grenoble, France. nicolau.elodie@gmail.com
Elodie
E
Nicolau
Lauriane
L
Kuhn
Rémy
R
Marchal
Yves
Y
Jouanneau
D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001483:Base Sequence; D001673:Biodegradation, Environmental; D042926:Cytochrome P-450 CYP4A / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000201:enzymology* / Q000235:genetics; D009566:Nitrates / Q000378:metabolism*; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics / Q000379:methods
D001426:Bacterial Proteins; D009566:Nitrates; D020543:Proteome; C040121:2-ethylhexyl nitrate; D042926:Cytochrome P-450 CYP4A