| Type: | Family | Name: | Acetaldehyde/propionaldehyde dehydrogenase, EutE/PduP-related |
| Description: | Members of this group function in ethanolamine [] and propanediol [] degradation pathways. Both pathways require coenzyme B12 (adenosylcobalamin, AdoCbl). Bacteria that harbor these pathways can use ethanolamine as a source of carbon and nitrogen, or propanediol as a sole carbon and energy source, respectively.The EutE protein is a putative CoA-dependent aldehyde dehydrogenase () proposed to catalyse the second step of the coenzyme B12 (adenosylcobalamin, AdoCbl)-dependent pathway of ethanolamine degradation [], converting acetaldehyde into acetyl-CoA. Mutational analysis has shown that EutE is involved in ethanolamine degradation [] and, on the basis of sequence similarity to AdhE alcohol dehydrogenase/acetaldehyde dehydrogenase () and aldehyde dehydrogenases (), it is believed to be an acetaldehyde dehydrogenase. Ethanolamine degradation pathway enzymes, including EutE, are encoded by the eut operon [, , ].PduP is encoded by the propanediol (pdu) operon and is involved in propanediol utilization []. The pathway of 1,2-propanediol degradation starts with the conversion of 1,2-propanediol to propionaldehyde by an AdoCbl-dependent propanediol dehydratase (, , ). Then, propionaldehyde is oxidized by propionaldehyde dehydrogenase to propionyl-CoA. Subsequently, propionyl-CoA can be metabolized either aerobically into pyruvate (presumably in three steps) or anaerobically into propionate (presumably in two steps) []. PduP is closely related to EutE and, therefore, has been predicted to be a CoA-dependent aldehyde dehydrogenase used in the pdu pathway for the conversion of propionaldehyde to propionyl-CoA [].Propanediol utilization is thought to be important for natural Salmonella populations, since propanediol is produced by the fermentation of the common plant sugars rhamnose and fucose [, ]. More than 1% of the Salmonella entericagenome is devoted to the utilization of propanediol and cobalamin biosynthesis. In vivo expression technology has indicated that propanediol utilization genes may be important for growth in host tissues, and competitive index studies with mice have shown that pdu mutations confer a virulence defect []. The pdu operon is contiguous and coregulated with the cobalamin (B12) biosynthesis cob operon, indicating that propanediol catabolism may be the primary reason for de novo B12 synthesis in Salmonella [, ].On the basis of sequence analysis, it has been suggested that the pdu/cob genes were lost by a common ancestor of Escherichia coliand Salmonella entericaand were reintroduced as a single fragment into the Salmonella lineage by a single horizontal gene transfer event from an exogenous source [, ]. | Short Name: | Acetald_propionald_DH-rel |
