The structural basis of interspecies bacterial communication

Title: The structural basis of interspecies bacterial communication

Speaker: Stephan Miller

Afiliation: Department of Chemistry and Biochemistry, Swarthmore College, USA

Host: Karina Xavier

Abstract

Bacteria communicate through a process termed quorum sensing, in which small chemical signals are produced and released into the environment.  As the population increases, these signal molecules (called autoinducers) accumulate and, when they reach sufficient concentration, are detected by other bacteria.  Bacteria modulate gene expression in response to these signals, and thus are able to regulate their behavior in a population-wide manner.  Many important behaviors are regulated by quorum sensing, including virulence, motility, and biofilm formation. While most autoinducers mediate communication within a bacterial species, a novel signal molecule, autoinducer-2 (AI-2), appears to be a universal signal molecule, facilitating interspecies signaling. We have shown that different species of bacteria recognize chemically distinct, but interconvertable, forms of AI-2.  Knowledge of the chemical identity of AI-2 recognized by a particular species is essential for the design of molecules that exploit quorum sensing to influence bacterial behavior.  Work in the Miller Lab focuses on the identification and structure determination of AI-2 receptor proteins from a variety of bacterial species, including the human pathogens Pseudomonas aeruginosa and Bacillus anthracis.  The structure of the AI-2 processing protein LsrF will also be presented.