MecE, MecB, MecC proteins orchestrate methyl group transfer during dichloromethane fermentation
Soder-Walz, Jesica M. (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Deobald, Darja (Helmholtz Centre for Environmental Research. Department Environmental Biotechnology)
Vicent i Huguet, Teresa (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Marco Urrea, Ernest (Universitat Autònoma de Barcelona. Departament d'Enginyeria Química, Biològica i Ambiental)
Adrian, Lorenz (Technische Universität Berlin)

Data:	2024
Resum:	Dichloromethane (DCM), a common hazardous industrial chemical, is anaerobically metabolized by four bacterial genera: Dehalobacter, Dehalobacterium, Ca. Dichloromethanomonas, Ca. Formimonas. However, the pivotal methyltransferases responsible for DCM transformation have remained elusive. In this study, we investigated the DCM catabolism of Dehalobacterium formicoaceticum strain EZ94, contained in an enriched culture, using a combination of biochemical approaches. Initially, enzymatic assays were conducted with cell-free protein extracts, after protein separation by blue native polyacrylamide gel electrophoresis. In the slices with the highest DCM transformation activity a high absolute abundance of the methyltransferase MecC was revealed by mass spectrometry. Enzymatic activity assays with heterologously expressed MecB, MecC, and MecE from strain EZ94 showed complete DCM transformation only when all three enzymes were present. Our experimental results, coupled with the computational analysis of MecB, MecC, and MecE sequences enabled us to assign specific roles in DCM transformation to each of the proteins. Our findings reveal that both MecE and MecC are zinc-dependent methyltransferases responsible for DCM demethylation and re-methylation of a product, respectively. MecB functions as a cobalamin-dependent shuttle protein transferring the methyl group between MecE and MecC. This study provides the first biochemical evidence of the enzymes involved in the anaerobic metabolism of DCM.
Ajuts:	Agencia Estatal de Investigación PID2022-138929OB-I00 Agencia Estatal de Investigación PID2019-103989RB-100 Agència de Gestió d'Ajuts Universitaris i de Recerca 2021/SGR-01008
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	In vitro activity test ; Anaerobic fermentation ; Heterologous expression ; Methyltransferase ; Metalloprotein ; Dehalobacterium
Publicat a:	Applied and Environmental Microbiology, Vol. 90, issue 10 (October 2024) , art. e00978-24, ISSN 1098-5336

DOI: 10.1128/aem.00978-24
PMID: 39320083

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