English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT

Released

Journal Article

Carnitine metabolism in the human gut: characterization of the two-component carnitine monooxygenase CntAB fromAcinetobacter baumannii

MPS-Authors
/persons/resource/persons237683

Reijerse,  Eduard J.
Research Department DeBeer, Max Planck Institute for Chemical Energy Conversion, Max Planck Society;

/persons/resource/persons237632

Laurich,  Christoph
Research Department DeBeer, Max Planck Institute for Chemical Energy Conversion, Max Planck Society;

External Resource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available
Citation

Massmig, M., Reijerse, E. J., Krausze, J., Laurich, C., Lubitz, W., Jahn, D., et al. (2020). Carnitine metabolism in the human gut: characterization of the two-component carnitine monooxygenase CntAB fromAcinetobacter baumannii. The Journal of Biological Chemistry, 295(37), 13065-13078. doi:10.1074/jbc.RA120.014266.


Cite as: http://hdl.handle.net/21.11116/0000-0007-D300-A
Abstract
Bacterial formation of trimethylamine (TMA) from carnitine in the gut microbiome has been linked to cardiovascular disease. During this process, the two-component carnitine monooxygenase (CntAB) catalyzes the oxygen-dependent cleavage of carnitine to TMA and malic semialdehyde. Individual redox states of the reductase CntB and the catalytic component CntA were investigated based on mutagenesis and electron paramagnetic resonance (EPR) spectroscopic approaches. Protein ligands of the flavin mononucleotide (FMN) and the plant-type [2Fe-2S] cluster of CntB and also of the Rieske-type [2Fe-2S] cluster and the mononuclear [Fe] center of CntA were identified. EPR spectroscopy of variant CntA proteins suggested a hierarchical metallocenter maturation, Rieske [2Fe-2S] followed by the mononuclear [Fe] center. NADH-dependent electron transferviathe redox components of CntB and within the trimeric CntA complex for the activation of molecular oxygen was investigated. EPR experiments indicated that the two electrons from NADH were allocated to the plant-type [2Fe-2S] cluster and to FMN in the form of a flavin semiquinone radical. Single-turnover experiments of this reduced CntB species indicated the translocation of the first electron onto the [Fe] center and the second electron onto the Rieske-type [2Fe-2S] cluster of CntA to finally allow for oxygen activation as a basis for carnitine cleavage. EPR spectroscopic investigation of CntA variants indicated an unusual intermolecular electron transfer between the subunits of the CntA trimerviathe "bridging" residue Glu-205. On the basis of these data, a redox catalytic cycle for carnitine monooxygenase was proposed.