Biophysical Society Conference | Tahoe 2022

Molecular Biophysics of Membranes

Poster Abstracts

46-POS Board 12 BIOPHYSICAL CHARACTERIZATION OF MAJOR FACILITATOR SUPERFAMILY TRANSPORTER STY4874 FROM SALMONELLA ENTERICA SEROVAR TYPHI Anam Tariq 1,4 ; Aqsa Shaheen 2 ; Randy Stockbridge 4 ; Moazur Rahman 1,3 ; 1 National Institute for Biotechnology and Genetic Engineering (NIBGE), PIEAS, Faisalabad, Pakistan 2 University of Gujrat, Department of Biochemistry and Biotechnology, Gujrat, Pakistan 3 University of the Punjab, School of Biological Sciences, Lahore, Pakistan 4 University of Michigan, Department of Molecular, Cellular and Developmental Biology, Ann Arbor, MI, USA Salmonellae are foodborne pathogens and the major cause of gastroenteritis in humans. Salmonellae express multidrug efflux transporters that play a key role in their drug resistance, which is becoming an increasing problem for therapeutic intervention. Despite their biomedical importance, the mechanisms underlying substrate transport by multidrug efflux transporters remain poorly understood. Here, we describe the biochemical characterization of a multidrug transporter belonging to the major facilitator superfamily from Salmonella enterica serovar Typhi. This transporter was found to be constitutively expressed in clinical isolates of Salmonella Typhi making it a potent drug target. To identify its role in multidrug resistance, a combination of cell-based functional assays, protein expression and purification, substrate binding analysis, and secondary structural analysis were conducted. We showed that this transporter is proton-dependent nature with broad-spectrum substrate specificity including fluoroquinolones and aminoglycosides. We further showed that it exists as structural monomer in DDM, and used CD spectroscopy and FTIR to show that, like its close homologues MdtM and MdfA from E. coli, STY4874 is rich in alpha helices. Efforts to crystallize and solve a high- resolution structure are ongoing. The structure elucidation of this transporter would greatly contribute in understanding the efflux mediated drug resistance mechanism in genus Salmonellae and in the structure-based drug design.

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