Overexpression of the BlaR1 membrane protein implicated in resistance to beta-lactams in Staphylococcus aureus

BELLUZO,B.S.; LLARRULL, L.I.

Villa Carlos Paz

Congreso; XLII Reunion Anual de la Sociedad Argentina de Biofisica; 2013

Sociedad Argentina de Biofisica

BlaR1 is a membrane receptor implicated in beta-lactam antibiotic resistance in Staphylococcus aureus. This protein is composed of various transmembrane helixes, followed by a cytoplasmic domain and an extracellular sensor domain capable of detecting de presence of antibiotics (1). The predicted cytoplasmic domain contains Zn(II)-dependent protease activity, and it has been proposed that it is activated in response to binding of the antibiotic to the sensor domain (2). Activated BlaR1 degrades the gene repressor BlaI, which triggers the expression of the BlaZ beta-lactamase. We are interested in the spectroscopic study of the signal transduction mediated by BlaR1. In order to overexpress this protein, we used active natural variants lacking the first three transmembrane helixes. We evaluated the expression as fusions to different soluble tags that were shown to help in the overexpression of several membrane proteins, and we are now developing a protocol of purification from inclusion bodies, denaturation and refolding. Acknowledgements The PEW Charitable Trusts, ANPCyT, CONICET   References H. Z. Zhang, C. J. Hackbarth, K. M. Chansky, H. F. Chambers, Science 291, 1962 (2001) L. I. Llarrull, S. Mobashery, Biochemistry 51, 4642 (2012).