Abstract
Many bacteria produce and respond to the quorum sensing signal autoinducer-2 (AI-2). Escherichia coli and Salmonella typhimurium are among the species with the lsr operon, an operon containing AI-2 transport and processing genes that are up regulated in response to AI-2. One of the Lsr proteins, LsrF, has been implicated in processing the phosphorylated form of AI-2. Here, we present the structure of LsrF, unliganded and in complex with two phospho-AI-2 analogues, ribose-5-phosphate and ribulose-5-phosphate. The crystal structure shows that LsrF is a decamer of (αβ)8-barrels that exhibit a previously unseen N-terminal domain swap and have high structural homology with aldolases that process phosphorylated sugars. Ligand binding sites and key catalytic residues are structurally conserved, strongly implicating LsrF as a class I aldolase.
Highlights
Many bacterial species control expression of specific genes thorough the production, release, and detection of small signal molecules called autoinducers
First identified as a regulator of bioluminescence in Vibrio harveyi [2,3], AI-2 has been shown to control a wide variety of behaviors in different species, including motility in Helicobacter pylori [4], division, stress response, and biofilm formation in Streptococcus mutans [5,6], virulence and formation of biofilms in Vibrio cholerae [7,8,9] and Staphylococcus epidermis [10], social and pluricellular behavior of Bacillus subtilis [11], and virulence in Erwinia carotovora ssp. carotovora [12]
We have been unable to detect the products of the LsrF reaction in vitro, either by NMR or TLC using radiolabled substrate, in the presence or absence of the other P-AI-2 processing enzyme LsrG
Summary
Many bacterial species control expression of specific genes thorough the production, release, and detection of small signal molecules called autoinducers. This process, termed quorum sensing, allows bacteria to regulate behavior in a populationdependant manner, effectively coordinating their activity. First identified as a regulator of bioluminescence in Vibrio harveyi [2,3], AI-2 has been shown to control a wide variety of behaviors in different species, including motility in Helicobacter pylori [4], division, stress response, and biofilm formation in Streptococcus mutans [5,6], virulence and formation of biofilms in Vibrio cholerae [7,8,9] and Staphylococcus epidermis [10], social and pluricellular behavior of Bacillus subtilis [11], and virulence in Erwinia carotovora ssp. Since many species produce and respond to AI-2, it is believed to facilitate interspecies communication, potentially allowing bacteria to modulate gene expression in response to both the concentration and species composition of bacteria in the local environment; some species of bacteria have been shown to respond to AI-2 produced by other species in co-culture experiments [13,14]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call