Elucidation of the antibiotic resistance mechanisms of BlaR1 and MecR1 through structural, biochemical and cellular investigation using cell-free protein expression

The emergence of broad-spectrum antibiotic resistance is leading to the appearance of an increasing number of multi-resistant pathogenic bacteria, or “”superbugs.”” During the past decade, the superbug Methicillin-Resistant Staphylococcus Aureus (MRSA) has become a major cause of drug-resistant infectious disease. MRSA strains are resistant to all beta-lactam antibiotics, including the commonly prescribed penicillins and cephalosporins. The rapid emergence of community-acquired MRSA strains affecting previously healthy individuals outside the healthcare environment is particularly distressing, as it presents an urgent public health threat. The objective of Dr. Solmaz Sobhanifar’s research project is to investigate antibiotic resistance mechanisms in MRSA. Dr. Sobhanifar is specifically studying beta-lactam sensor/signal transducer proteins, BlaR1 and MecR1, which sense beta-lactam antibiotic levels. Understanding the structures of BlaR1 and MecR1 and how their mechanisms of action permit survival of MRSA during antibiotic treatment would considerably assist drug-design efforts. Dr. Sobhanifar is using x-ray crystallography and NMR spectroscopy to conduct the first detailed molecular structural analysis of these important drug resistance signaling proteins. Obtaining the necessary quantity of materials for structural investigation has proven notoriously challenging, so a “”cell-free”” protein expression approach will be used to obtain sufficient levels of BlaR1 and MecR1 for structural studies. This approach also facilitates selective amino acid labeling, which is important for x-ray- and NMR-based investigations. In partnership with the Centre for Drug Research and Development at UBC, the acquired structural and biochemical data will be used, in conjunction with unique small molecule and natural product chemical libraries, to screen and optimize novel lead inhibitors against BlaR1/MecR1-induced antibiotic resistance in MRSA. This will hopefully provide new therapeutic approaches to manage MRSA in the future.