Sarah Khalil

Year: Senior

Major(s):  Chemistry with emphasis in Biochemistry

Mentor: Liu, Dali

Department: Chemistry & Biochemistry

Project Title: Induced Promiscuity of AiiB to Expand Quorum-Quenching Abilities

Project Abstract: Quorum-sensing involves the interaction between chemical signals and bacterial receptor proteins so that bacteria may act as a unit in their host organism, such as when a group of bacterial pathogens are about to attack a human host. Quorum-quenching cuts off the quorum-sensing mechanism, thus preventing bacteria from acting as a unit. N-acyl homoserine lactonases are protein catalysts that are heavily involved in quenching mechanisms. One lactonase, AiiB, is a typical quorum-quenching enzyme. My goal is to take mutated AiiB and examine its promiscuity through structural and kinetic studies, or to take manipulated AiiB and see how it binds different substrates so as to determine the mechanism by which it binds and catalyzes promiscuous reactions. Comparing these results to wild type AiiB allows us to determine the impact that these manipulations have on the promiscuity of the lactonase reaction. Insight into the promiscuity of AiiB can help us eventually design a version of the enzyme that can stop the attack of antibiotic-resistant pathogenic bacteria in our bodies. I will be working under the guidance of Dr. Dali Liu, an expert in N-acyl homoserine lactonase activity.