2‑Deoxy-4-<i>epi</i>-<i>scyllo</i>-inosose (DEI) is the Product\nof EboD, a Highly Conserved Dehydroquinate\nSynthase-like Enzyme in Bacteria and Eustigmatophyte Algae

A cryptic\ncluster of genes, known as the ebo cluster,\nhas been\nfound in a variety of genomic contexts among bacteria and algae. In <i>Pseudomonas fluorescens</i> NZI7, the ebo cluster (a.k.a. EDB\ncluster) is involved in the bacterial repellent mechanism against\nnematode grazing. In cyanobacteria, the cluster plays a role in the\ntransport of the scytonemin monomer from the cytosol to the periplasm.\nDespite their broad distribution and interesting phenotypes, neither\nthe pathway nor the functions of the enzymes are known. Here we show\nthat EboD proteins from the ebo clusters in <i>Nostoc punctiforme</i> and <i>Sporocytophaga myxococcoides</i> catalyze the cyclization\nof mannose 6-phosphate to a novel cyclitol, 2-deoxy-4-<i>epi</i>-<i>scyllo</i>-inosose. The enzyme product is postulated\nto be a precursor of a signaling molecule or a transporter in the\norganisms. This study sheds the first light onto ebo/EDB pathways\nand established a functionally distinct enzyme that extends the diversity\nof sugar phosphate cyclases.