Proteome Analysis of B. subtilis in Response to Calcium
- *Corresponding Author:
- Delfina C. Domínguez
500 W University Ave. Rm 420
College of Health Sciences, El Paso
Texas, The University of Texas at El Paso
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Received date: July 01, 2011; Accepted date: August 08, 2011; Published date: Augutst 31, 2011
Citation: Domníguez DC, Lopes R, Holland IB, Campbell AK (2011) Proteome Analysis of B. subtilis in Response to Calcium. J Anal Bioanal Techniques S6:001. doi:10.4172/2155-9872.S6-001
Copyright: © 2011 Domníguez D, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
While the role of calcium binding proteins (CaBPs) in cell signaling pathways and homeostasis is well established in eukaryotic cells, the physiological function of CaBPs in prokaryotes is unknown. Although several CaBPs have been identified and sequences predicted in a variety of prokaryotic genomes, biochemical and functional characterization is lacking. We hypothesize that CaBPs play an important role in Ca2+ homeostasis and that Ca2+ ions regulate several processes in bacterial cells. The purpose of this work was to study the effects of Ca2+ in the B. subtilis proteome, to identify CaBPs altered (increased or decreased) by the addition of Ca2+ -chelators (EGTA, BAPTA) or CaCl2, and to examine Ca2+ homeostasis in B. subtilis cells utilizing various analytical techniques. 45Ca-autoradiography and antibody-crossreactivity were used to detect CaBPs. These proteins were identified by LC-MS/MS. Intracellular calcium levels [Ca2+]i were measured using the photoprotein aequorin. Our results show that remarkable global changes in protein abundance occurred in the B. subtilis proteome as a result of CaCl2 or chelator 58 treatments compared to control cells. Six proteins appeared to be modulated by high levels of extracellular Ca2+. These proteins were increased after Ca2+ -chelator treatments and reduced upon Ca2+ addition. Moreover, these proteins bound radioactive 45Ca2+, and showed a shift in molecular weight in the presence of Ca2+ /EGTA. B. subtilis cells thightly regulate cytosolic Ca2+ levels. Taken together, these results suggest an important role of Ca2+ ions in B. subtilis.