Elucidation of probable responses to molybdate stress in Desulfovibrio alaskensis by proteome analysis.

R.R. NAIR; C. SILVEIRA; M.G. ALMEIDA; J. J. G. MOURA; M.G. RIVAS

Lisboa

Simposio; ISMEC (International Symposia on Metal Complexes).; 2012

Metals play many important structural and functional activities in cell metabolism as they serve as essential cofactors for a variety of enzymatic reactions. However, when present in high levels, they can become toxic for the cell. In the present study we investigated the effect of high molybdate (Mo) concentrations on Desulfovibrio alaskensis G20 (DaG20) cells at a proteomic level. Growth studies were carried out to determine the molybdate concentration yielding 70% cell growth inhibition. Two-dimensional gel electrophoresis of both soluble and membrane fractions of the Mo stressed cells were compared with the respective fractions from nonstressed (normal) cells (Figure 1). The identity of proteins, up- or down-regulated was assessed by MALDI-TOF mass spectrometry. Our results show that the proteins affected by the stress conditions are mainly involved in processes related to energy metabolism, amino acid, purines and pyrimidine biosynthesis, stress response and transport proteins. By discussing the probable roles played by the identified proteins, we attempted to have a deeper understanding on the impact of high Mo levels in the environment on sulphate reducing bacteria.