A Novel AI-2 Synthase for Cross-Domain Communication

Abstract

Bacterial cells communicate using quorum sensing, a process that involves the exchange of signal molecules known as autoinducers. While autoinducers were once thought to be species specific, the Bassler lab has characterized a “universal” autoinducer called AI-2. Interdomain communication was discovered when mammalian cells were found to produce a mimic of AI-2 capable of binding to AI-2 receptors in Vibrio harveyi, inducing bioluminescence. While the structure of this mimic has not been reported, recent data suggest that the mimic is xylosone. Despite the absence of a known enzyme for xylosone production in mammalian cells, previous literature characterizes pyranose oxidases as potential xylosone synthases, found throughout fungi and bacteria. In this thesis, it is shown that a fungal pyranose oxidase produces an AI-2 mimic, as measured by both high resolution mass spectrometry and a bioactivity assay in V. harveyi. This research lays the foundation for future work that could provide insights into AI-2 mediated chemical communication between bacteria and eukaryotes.