Comprehensive proteome profiling of the Fe(III)‐reducing myxobacterium Anaeromyxobacter dehalogenans 2CP‐C during growth with fumarate and ferric citrate

Abstract

Anaeromyxobacter dehalogenans is a microaerophilic member of the delta-proteobacteria which is able to utilize a wide range of electron acceptors, including halogenated phenols, U(VI), Fe(III), nitrate, nitrite, oxygen and fumarate. To date, the knowledge regarding general metabolic activities of this ecologically relevant bacterium is limited. Here, we present a first systematic 2-D reference map of the soluble A. dehalogenans proteome in order to provide a sound basis for further proteomic studies as well as to gain first global insights into the metabolic activities of this bacterium. Using a combination of 2-DE and MALDI-TOF-MS, a total of 720 proteins spots were identified, representing 559 unique protein species. Using the proteome data, altogether 50 metabolic pathways were found to be expressed during growth with fumarate as primary electron acceptor. An analysis of the pathways revealed an extensive display of enzymes involved in the catabolism and anabolism of a variety of amino acids, including the unexpected fermentation of lysine to butyrate. Moreover, using the reference gel as basis, a semi-quantitative analysis of protein expression changes of A. dehalogenans during growth with ferric citrate as electron acceptor was conducted. The adaptation to Fe(III) reducing conditions involved the expression changes of a total of 239 proteins. The results suggest that the adaptation to Fe(III) reductive conditions involves an increase in metabolic flux through the tricarboxylic acid cycle, which is fueled by an increased catabolism of amino acids.