Identification of the ATPase Subunit of the Primary Maltose Transporter in the Hyperthermophilic Anaerobe Thermotoga maritima.

is a hyperthermophilic anaerobic bacterium that produces molecular hydrogen (H) by fermentation. It catabolizes a broad range of carbohydrates through the action of diverse ABC transporters. However, in and related species, highly similar genes with ambiguous annotation obscure a precise understanding of genome function. In , three putative genes, all annotated as ATPase subunits, exhibited high identity to each other. To distinguish between these genes, disruption mutants were constructed by gene replacement, and the resulting mutant cell lines were characterized. Only a disruption of produced a defect in maltose catabolism. To verify that the mutant phenotype arose specifically from inactivation, the mutation was repaired by recombination, and maltose catabolism was restored. This study demonstrates the importance of a maltose ABC-type transporter and its relationship to sugar metabolism in The application and further development of a genetic system was used here to investigate gene paralogs in the hyperthermophile The occurrence of three ABC transporter ATPase subunits all annotated as was evaluated using a combination of genetic and bioinformatic approaches. The results clarify the role of only one gene in maltose catabolism in a nonmodel organism noted for fermentative hydrogen production.