CLONING, SEQUENCING, AND MUTATIONAL ANALYSIS OF THE HYB-OPERON ENCODING ESCHERICHIA-COLI HYDROGENASE-2

The genes encoding the two structural subunits of Escherichia coli hyd rogenase 2 (HYD2) have been cloned and sequenced, They occur in an ope ron (hyb) which contains seven open reading frames. An hyb deletion mu tant (strain AP3) failed to grow on dihydrogen-fumarate medium and als o produced very low levels of HYD1. All seven open reading frames are required for restoration of wild-type levels of active HYD2 in AP3. Th e hyb operon was mapped at 65 min on the E. coli chromosome.