Catalyzes the dehydration of 6-deoxy-6-sulfo-D-gluconate to 2-dehydro-3,6-dideoxy-6-sulfo-D-gluconate. Is involved in a degradation pathway of sulfoquinovose (SQ) that allows P.putida SQ1 to use SQ as the sole carbon and energy source for growth. 6-deoxy-6-sulfo-D-gluconate = 2-dehydro-3,6-dideoxy-6-sulfo-D-gluconate + H2O Binds 1 [4Fe-4S] cluster. Homodimer. Is highly up-regulated during growth on sulfoquinovose, compared to growth on glucose or succinate (at protein level). Belongs to the IlvD/Edd family.