Anaerobic naphthalene degradation
Hi, I am Max.
Polycyclic aromatic carbons are persistent in nature and many exhibit toxic and cancerogenic effects. During my PhD thesis, I was investigating key enzymes involved in the degradation of the polycyclic aromatic model compound naphthalene in strictly anaerobic bacteria. In the absence of oxygen, some strictly anaerobic bacteria bacteria are able to use naphthalene as a carbon and energy source. After carboxylation and thioesterification, the two aromatic rings of the 2-naphthoyl-CoA intermediate are dearomatized by reductases. We isolated and characterized the enzymes involved in the dearomatization of the first ring of the of the naphthoyl-CoA intermediate that belong to the old yellow enzymes family with flavin and FeS cofactors. We solved the crystal structure aof 2-naphthoyl-CoA reductase and unraveled an extremely low-potential hydride transfer mechanism involved in the dearomatization of the naphthyl ring structure by electrochemical, spectroscopic and kinetic studies.
I am currently working on oxygen-independent hydroxylases from anaerobic organisms that are evaluated for their use in biotechnological applications.
Left: Step-wise two-electron reductions of the 2-naphthoyl-CoA intermediate in naphthalene-degrading bacteria by flavin-dependent dehydrogenases. Right: Overall X-ray structure of monomeric 2-naphthoyl-CoA reductase (NCR) belonging to the "Old yellow enzyme family" TIM barrel domain (yellow) and by two α/β domains (blue). Reductive 2-naphthoyl-CoA reduction is accomplished at an active site FMN cofactor via extremely low-potential hydride transfer.