LuxS manual notes

Automated deep-research providers were unavailable for this host, so this is a compact manual review against the cached UniProt and PMID records.

Function

• UniProtKB:P45578 describes LuxS as a cytosolic S-ribosylhomocysteine lyase that converts S-ribosylhomocysteine to homocysteine and 4,5-dihydroxy-2,3-pentadione, with one inferred Fe cation per subunit and a homodimeric quaternary structure.
• Schauder et al. showed that LuxS is the AI-2 synthase and that its substrate is S-ribosylhomocysteine, which is cleaved to homocysteine plus the AI-2 precursor/product PMID:11489131.
• Surette et al. identified luxS-family genes responsible for AI-2 production in Vibrio harveyi, Salmonella typhimurium, and E. coli; the E. coli O157:H7 luxS gene complemented E. coli DH5alpha for AI-2 production PMID:9990077.
• The DeLisa et al. microarray study used an E. coli W3110 luxS mutant unable to synthesize AI-2 to define an AI-2-responsive transcriptional state, supporting the curated E. coli quorum-sensing process annotation PMID:11514505.

Annotation decisions

• Accept S-ribosylhomocysteine lyase activity rows: the molecular function is the experimentally supported core activity.
• Accept quorum sensing rows but treat them as downstream from the same core lyase chemistry: LuxS produces the DPD precursor for AI-2 rather than sensing AI-2 itself.
• Add L-methionine cycle as a new direct process annotation: in bacteria that use the Pfs/MtnN plus LuxS route, LuxS performs the second SAH-processing step and releases homocysteine for remethylation.
• Keep cytosol rows: LuxS has cytosolic proteomics calls and a cytosolic IBA assertion.
• Remove the generic DnaK protein binding row: the IntAct row may report a physical interaction, but there is no narrower supported LuxS molecular function to curate from a large-scale pull-down alone.
• Modify generic metal ion binding to iron ion binding; the more precise term is already asserted from the LuxS family.