CLONING AND SEQUENCING OF THE GENE ENCODING THE CU,ZN-SUPEROXIDE DISMUTASE OF HAEMOPHILUS-DUCREYI

The sodC gene of Haemophilus ducreyi was cloned and sequenced. The ded uced amino acid sequence of this protein exhibited 71.6% identity and 81.8% similarity to the H. influenzae and H. parainfluenzae copper (Cu ), zinc (Zn)-superoxide dismutase (SOD) enzymes. This gene was localiz ed to a 2.2-kb H. ducreyi chromosomal DNA insert in plasmid pHdSOD. SO D activity was expressed in cell-free extracts of Escherichia coli con taining the recombinant plasmid pHdSOD and was localized to the peripl asmic space. The Cu,Zn-SOD produced by the H. ducreyi sodC gene did no t complement the aerobic growth defect of an E. coli SOD-deficient mut ant.