Molybdenum Induces the Expression of a Protein Containing a New Heterometallic Mo-Fe Cluster in Desulfovibrio alaskensis

• Published in: Biochemistry (Easton) 2009-02, Vol.48 (5), p.873-882
• Main Authors: Rivas, Maria G, Carepo, Marta S. P, Mota, Cristiano S, Korbas, Malgorzata, Durand, Marie-Claire, Lopes, Ana T, Brondino, Carlos D, Pereira, Alice S, George, Graham N, Dolla, Alain, Moura, José J. G, Moura, Isabel
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Bacterial Proteins; Bacterial Proteins - biosynthesis; Bacterial Proteins - genetics; Biochemistry, Molecular Biology; Desulfovibrio; Desulfovibrio - chemistry; Desulfovibrio - physiology; Gene Expression Regulation, Bacterial; Gene Expression Regulation, Bacterial - physiology; Iron; Iron - metabolism; Life Sciences; Metalloproteins; Metalloproteins - biosynthesis; Metalloproteins - genetics; Molecular Sequence Data; Molybdenum; Molybdenum - chemistry; Molybdenum - physiology
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi801773t

The characterization of a novel Mo-Fe protein (MorP) associated with a system that responds to Mo in Desulfovibrio alaskensis is reported. Biochemical characterization shows that MorP is a periplasmic homomultimer of high molecular weight (260 ± 13 kDa) consisting of 16−18 monomers of 15321.1 ± 0.5 Da. The UV/visible absorption spectrum of the as-isolated protein shows absorption peaks around 280, 320, and 570 nm with extinction coefficients of 18700, 12800, and 5000 M−1 cm−1, respectively. Metal content, EXAFS data and DFT calculations support the presence of a Mo-2S-[2Fe-2S]-2S-Mo cluster never reported before. Analysis of the available genomes from Desulfovibrio species shows that the MorP encoding gene is located downstream of a sensor and a regulator gene. This type of gene arrangement, called two component system, is used by the cell to regulate diverse physiological processes in response to changes in environmental conditions. Increase of both gene expression and protein production was observed when cells were cultured in the presence of 45 μM molybdenum. Involvement of this system in Mo tolerance of sulfate reducing bacteria is proposed.