Publications

• Anaerobic toluene-catabolic pathway in denitrifying Thauera aromatica: activation and beta-oxidation of the first intermediate, (R)-(+)-benzylsuccinate.

  Leutwein C., Heider J.

  Anaerobic catabolism of toluene is initiated by addition of the methyl group of toluene to the double bond of a fumarate cosubstrate to yield the first intermediate, benzylsuccinate. This reaction is catalysed by the glycyl-radical enzyme benzylsuccinate synthase, as shown for the denitrifying bac ... >> More

  Anaerobic catabolism of toluene is initiated by addition of the methyl group of toluene to the double bond of a fumarate cosubstrate to yield the first intermediate, benzylsuccinate. This reaction is catalysed by the glycyl-radical enzyme benzylsuccinate synthase, as shown for the denitrifying bacterium Thauera aromatica. Benzylsuccinate is further oxidized to benzoyl-CoA, the central intermediate of anaerobic degradation of aromatic compounds. The authors show here by experiments with cell extracts of toluene-grown T. aromatica that the pathway of benzylsuccinate oxidation requires activation of the free acid to a CoA-thioester, catalysed by a toluene-induced, reversible succinyl-CoA-dependent CoA-transferase. The product of the CoA-transferase reaction, benzylsuccinyl-CoA, is oxidized to benzoyl-CoA and succinyl-CoA in extracts of toluene-grown cells, adding proof to the proposed anaerobic toluene-catabolic pathway. The stereochemical preferences of the enzymes catalysing formation and activation of benzylsuccinate have been analysed. Benzylsuccinate synthase was found to produce exclusively (R)-(+)-benzylsuccinate, although the proposed reaction mechanism of this enzyme proceeds via radical intermediates. In accordance, the reaction of succinyl-CoA:benzylsuccinate CoA-transferase is also specific for (R)-(+)-benzylsuccinate and does not proceed with the (S)-(-)-enantiomer. << Less

  Microbiology (Reading) 145:3265-3271(1999) [PubMed] [EuropePMC]

  This publication is cited by 1 other entry.

• (R)-benzylsuccinyl-CoA dehydrogenase of Thauera aromatica, an enzyme of the anaerobic toluene catabolic pathway.

  Leutwein C., Heider J.

  The first intermediate of anaerobic toluene catabolism, (R)-benzylsuccinate, is formed by enzymic addition of the methyl group of toluene to a fumarate cosubstrate and is subsequently activated to (R)-2-benzylsuccinyl-CoA. This compound is then oxidised to benzoyl-CoA and succinyl-CoA by a specifi ... >> More

  The first intermediate of anaerobic toluene catabolism, (R)-benzylsuccinate, is formed by enzymic addition of the methyl group of toluene to a fumarate cosubstrate and is subsequently activated to (R)-2-benzylsuccinyl-CoA. This compound is then oxidised to benzoyl-CoA and succinyl-CoA by a specific beta-oxidation pathway. The enzyme catalysing the first oxidation step of this pathway, (R)-benzylsuccinyl-CoA dehydrogenase, is encoded by the bbsG gene in Thauera aromatica. It was functionally overproduced in Escherichia coli, purified and characterised. The enzyme is a homotetramer with a subunit size of 45 kDa and contains one FAD per subunit. It is highly specific for (R)-benzylsuccinyl-CoA and is inhibited by (S)-benzylsuccinyl-CoA. An apparent K(m) value of 110+/-10 micro M was obtained for (R)-benzylsuccinyl-CoA. The reaction product of (R)-benzylsuccinyl-CoA dehydrogenase was identified as (E)-benzylidene-succinyl-CoA by comparison with the chemically synthesised compound, which was obtained via a new synthetic procedure. (R)-Benzylsuccinyl-CoA dehydrogenase was detected as a specifically substrate-induced protein in toluene- and m-xylene-grown cells of several bacterial species, using enzyme activity and immunological detection. << Less

  Arch. Microbiol. 178:517-524(2002) [PubMed] [EuropePMC]