Molecular cloning and sequencing of the sodB gene from a heterocystous cyanobacterium Anabaena sp PCC 7120

Superoxide dismutase (Sod) plays an important role in all aerobic organisms . The sodB gene of a heterocystous cyanobacterium Anabaena sp. PCC 7120 was cloned and sequenced. The Sod protein is predicted to have 199 amino acids and a molecular mass of 22.5 kDa. Sequence comparison among SodB from cyan obacteria and chloroplasts revealed that the sodB gene indeed encodes an ir on-Sod. Northern blot analysis showed that the sodB gene of Anabaena sp. PC C 7120 is transcribed as a single gene and its expression was up-regulated when the cells were subjected to a shift from a nitrogen repletion conditio n to a nitrogen depletion condition. (C) 2000 Elsevier Science B.V. All rig hts reserved.