Reductive Acetyl-CoA pathway

The carbon oxides CO and CO₂ are used as a carbon source by several different types of microorganisms. Microbes living under anaerobic conditions can reduce CO₂ directly to CO, which is used within the reductive acetyl-CoA pathway to synthesize acetyl-CoA.



We investigate the mechanism of the enzymes of this pathway and study the role of their accessory proteins:
 

Carbon monoxide dehydrogenase - CODH

Ni,Fe-containing carbon monoxide dehydrogenases catalyze the reversible reduction of CO₂ to CO. The active site of carbon monoxide dehydrogenases contains a [NiFe₄S₄OH] cluster, which binds and converts CO and CO₂. We want to determine the mechanism of this enzyme and want to find out why the enzyme is able to reduce CO₂ without an over potential.
 

CooC-ATPases

The [NiFe₄S₄OH] cluster of CODHases is assembling spontaneously, but requires helper proteins. To insert Ni²⁺ into the heterometal cluster the ATPase CooC is needed, whose structure and function we are investigating.
 

Acetyl-coenzyme A synthase - ACS

Acetyl-Coenzyme A synthases catalyze the condensation of CO, coenzym A and a methyl cation. This reaction is catalyzed at a Ni-Ni-[4Fe4S] cluster- Details of the reaction mechanism are hardly understood.
 

Corrinoid iron/sulfur protein - CoFeSP

The corrinoid iron/sulfur protein serves as a methyl-transfer agent between the methyltetrahydrofolate dependent methyltransferase and acetyl-CoA synthase. CoFeSP allows a unique methyltransfer between two metal centres.