Stereochemical Insights into the Anaerobic Degradation of 4-Isopropylbenzoyl-CoA in the Denitrifying Bacterium Strain pCyN1
| Autor: | Jens Christoffers, Patrick Becker, Marc Schmidtmann, René Jarling, Nevenka Cakić, Heinz Wilkes, Julian Küppers, Marvin Dörries, Ralf Rabus |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Models
Molecular Thauera Thauera aromatica Stereochemistry 010402 general chemistry Hydroxylation 01 natural sciences Catalysis Stereocenter chemistry.chemical_compound Coenzyme A Anaerobiosis biology 010405 organic chemistry Chemistry Organic Chemistry Diastereomer Betaproteobacteria Stereoisomerism General Chemistry biology.organism_classification 0104 chemical sciences Rhodopseudomonas Biodegradation Environmental Denitrification Monoterpenes Cymenes Stereoselectivity Rhodopseudomonas palustris Oxidation-Reduction Isopropyl Methyl group |
| Zdroj: | Chemistry (Weinheim an der Bergstrasse, Germany). 25(18) |
| ISSN: | 1521-3765 |
| Popis: | The constitutions and absolute configurations of two previously unknown intermediates, (1S,2S,4S)-2-hydroxy-4-isopropylcyclohexane-1-carboxylate and (S)-3-isopropylpimelate, of anaerobic degradation of p-cymene in the bacterium Aromatoleum aromaticum pCyN1 are reported. These intermediates (as CoA esters) are involved in the further degradation of 4-isopropylbenzoyl-CoA formed by methyl group hydroxylation and subsequent oxidation of p-cymene. Proteogenomics indicated 4-isopropylbenzoyl-CoA degradation involves (i) a novel member of class I benzoyl-CoA reductase (BCR) as known from Thauera aromatica K172 and (ii) a modified β-oxidation pathway yielding 3-isopropylpimeloyl-CoA analogously to benzoyl-CoA degradation in Rhodopseudomonas palustris. Reference standards of all four diastereoisomers of 2-hydroxy-4-isopropylcyclohexane-1-carboxylate as well as both enantiomers of 3-isopropylpimelate were obtained by stereoselective syntheses via methyl 4-isopropyl-2-oxocyclohexane-1-carboxylate. The stereogenic center carrying the isopropyl group was established using a rhodium-catalyzed asymmetric conjugate addition. X-ray crystallography revealed that the thermodynamically most stable stereoisomer of 2-hydroxy-4-isopropylcyclohexane-1-carboxylate is formed during p-cymene degradation. Our findings imply that the reductive dearomatization of 4-isopropylbenzoyl-CoA by the BCR of A. aromaticum pCyN1 stereospecifically forms (S)-4-isopropyl-1,5-cyclohexadiene-1-carbonyl-CoA. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Plný text