Catalyzes the intramolecular carbocycle formation from D-glucose-6-phosphate to 2-deoxy-scyllo-inosose (DOI). D-glucose 6-phosphate = 2-deoxy-L-scyllo-inosose + phosphate Binds 1 Co(2+) ion per subunit. Strongly inhibited by EDTA, zinc and Cu(2+). Optimum pH is 7.5-8.5. Optimum temperature is 46 degrees Celsius. Metabolic intermediate biosynthesis; 2-deoxystreptamine biosynthesis; 2-deoxystreptamine from D-glucose 6-phosphate: step 1/4. Antibiotic biosynthesis; butirosin biosynthesis. Was isolated as a heterodimeric enzyme comprising of BtrC and a smaller polypeptide further identified as PdxT by sequence homology (PubMed:10344560). Homodimer in solution (PubMed:17879343). Belongs to the sugar phosphate cyclases superfamily. DOI synthase family.