Major
Chemistry
Research Abstract
Adenosine Triphosphate Binding Cassette (ABC) transporters constitute a superfamily of active transporters embedded in the cellular membrane. They consist of two highly conserved nucleotide-binding subunits which bind and hydrolyze ATP, and two diverse transmembrane subunits which provide a pathway for the substrate to pass through the membrane. ABC transporters serve a broad range of vital functions. Various conditions like cystic fibrosis and Stargardt disease are caused by defunct ABC transporters, and certain medical complications like antibiotic drug resistance are linked to promiscuous ABC transporters. Despite the importance of these transporters in crucial biological processes, the mechanisms of many transporters are yet to be solved. While many universal features of ABC transporters have been identified, the step-by-step process by which individual transporters move the substrate are a mystery. / To further understand the mechanism of ABC transporters, we are studying the E. coli methionine ABC importer MetNI. Because the bacterium needs to vary methionine import based on cellular needs, MetNI ATPase activity and coupled substrate transport must be properly regulated. Our current goal is to understand the mechanistic details of MetNI ATP binding and hydrolysis using a real-time ATPase assay. Here we present our preliminary work on analyzing the kinetics of MetNI ATP usage under varying conditions and with different mutations. This detailed study of MetNI kinetics will ultimately provide insight into the mechanism of methionine import, which may be more broadly applicable to the ABC transporter superfamily.
Faculty Mentor/Advisor
Janet Yang
Included in
Determining the Mechanical Properties of the E. coli Methionine Transporter
Adenosine Triphosphate Binding Cassette (ABC) transporters constitute a superfamily of active transporters embedded in the cellular membrane. They consist of two highly conserved nucleotide-binding subunits which bind and hydrolyze ATP, and two diverse transmembrane subunits which provide a pathway for the substrate to pass through the membrane. ABC transporters serve a broad range of vital functions. Various conditions like cystic fibrosis and Stargardt disease are caused by defunct ABC transporters, and certain medical complications like antibiotic drug resistance are linked to promiscuous ABC transporters. Despite the importance of these transporters in crucial biological processes, the mechanisms of many transporters are yet to be solved. While many universal features of ABC transporters have been identified, the step-by-step process by which individual transporters move the substrate are a mystery. / To further understand the mechanism of ABC transporters, we are studying the E. coli methionine ABC importer MetNI. Because the bacterium needs to vary methionine import based on cellular needs, MetNI ATPase activity and coupled substrate transport must be properly regulated. Our current goal is to understand the mechanistic details of MetNI ATP binding and hydrolysis using a real-time ATPase assay. Here we present our preliminary work on analyzing the kinetics of MetNI ATP usage under varying conditions and with different mutations. This detailed study of MetNI kinetics will ultimately provide insight into the mechanism of methionine import, which may be more broadly applicable to the ABC transporter superfamily.
