Dehalogenation of halobenzoates in denitrifying bacteria
Matthias Boll (University of Leipzig)
The anaerobic degradation halogenated aromatics has usually been associated with membrane-bound reductive dehalogenases, corrinoid-containing key enzymes of anaerobic organohalide respiration. In contrast, the complete oxidative degradation of halobenzoates in anaerobes has been reported in denitrifying, sulfate-reducing, Fe(III)-respiring and in anaerobic phototrophic bacteria. The catabolism of halobenzoates is supposed to proceed via CoA esters and includes a so far unknown reductive dehalogenation step. In our project we will study the degradation of various halobenzoates in the denitrifying model organisms Thauera chlorobenzoica and Azoarcus evansii. The major objectives are: (i) determination of the substrate/product of the dehalogenation reactions by CoA-ester metabolome analysis and by the in vitro assays; (ii) characterization of the reductive enzymatic dehalogenation); (iii) characterization of key enzymes involved in halobenzoate catabolism; and (iv) the determination of the minimal enzymatic prerequisites for growth on halobenzoates.
Scheme of haloaromatics dehalogenation and degradation mediated by denitrifying bacteria
Tiedt O, Mergelsberg M, Boll K, Müller M, Adrian L, Jehmlich N, von Bergen M, Boll M.
ATP-Dependent C-F Bond Cleavage Allows the Complete Degradation of 4-Fluoroaromatics without Oxygen
MBio. 2016 Aug 9;7(4). pii: e00990-16. doi: 10.1128/mBio.00990-16.
Kuntze K., Kiefer P., Baumann S., Seifert J., von Bergen M., Vorholt J.A., Boll M.
Enzymes involved in the anaerobic degradation of meta-substituted halobenzoates
Mol. Microbiol. 2011, Nov;82(3):758-69
Kung, J.W., Baumann, S., von Bergen, M., Müller, M., Hagedoorn, P.-L., Hagen, W.R. and Boll, M. (2010) Reversible biological Birch reduction at an extremely low redox potential. J Am Chem Soc 132, 9850-9856.