Proteomic analysis of the purple sulfur bacterium Candidatus “Thiodictyon syntrophicum” strain Cad16T isolated from Lake Cadagno

Abstract

Lake Cadagno is characterised by a compact chemocline with high concentrations of purple sulfur bacteria (PSB). 2D-DIGE was used to monitor the global changes in the proteome of Candidatus “Thiodictyon syntrophicum” strain Cad16T both in the presence and absence of light. This study aimed to disclose details regarding the dark CO2 assimilation of the PSB, as this mechanism is often observed but is not yet sufficiently understood. Our results showed the presence of 17 protein spots that were more abundant in the dark, including three enzymes that could be part of the autotrophic dicarboxylate/4-hydroxybutyrate cycle, normally observed in archaea.

Keywords

• Phototrophic sulfur bacteria
• Dark CO2 assimilation
• Granules of poly(3-hydroxybutyrate) (PHB)
• Dicarboxylate/4-hydroxybutyrate (DC/HB) cycle