Die Gene der (1-Methylalkyl)succinat-Synthase im anaeroben n-Alkanabbau des Betaproteobakteriums Stamm HxN1

Abstract

The betaproteobacterial strain HxN1 completely oxidizes the n-alkanes pentane to octane under denitrifying conditions. The activation of n-alkanes is catalyzed by the glycyl radical enzyme (1-methylalkyl)succinate synthase, whose encoding mas genes are organized in an operon in strain HxN1. In this study, a genetic system for strain HxN1 was developed. The deletion of masD, encoding the catalytic subunit of the enzyme, revealed the presence of a second identical mas operon in strain HxN1. The physiological characterization of the mutant confirmed in vivo the anaerobic activation of n-alkanes by (1-methylalkyl)succinate synthase. The phenotype was restored by complementation with the entire mas operon. Regarding regulation, the mas operon was induced by several hydrocarbons and expression was not inhibited in the presence of a carboxylic acid or a sugar as second carbon source. Furthermore, it was attempted to crystallize the (1-methylalkyl)succinate synthase of strain HxN1.