ARYLSULFATASE FROM ALTEROMONAS-CARRAGEENOVORA

Arylsulphatase activity was identified in cultures of the marine bacte rium Alteromonas carrageenovora, using methylumbelliferyl sulphate as substrate. In contrast with most other microbial arylsulphatases, aryl sulphatase production in A. carrageenovora was not repressed by sulpha te. The structural gene of arylsulphatase (atsA) was cloned and sequen ced. An ORF of 984 bp was found, specifying a primary translation prod uct of 328 amino acids with a molecular mass of 35 797 Da. Arylsulphat ase was partially purified from cell extracts of both A. carrageenovor a and recombinant Escherichia coli. Both the recombinant and native en zymes exhibited a pi of 5.5, a Michaelis constant for methylumbellifer yl sulphate of 68 mu M, and a molecular mass of approximately 35 000 D a in SDS-PAGE analysis. Secondary structure comparisons using hydropho bic cluster analysis suggest functional analogies between the arylsulp hatase of A. carrageenovora, that of Mycobacterium leprae and a 33.5 k Da protein from Porphyromonas gingivalis. It is speculated that these proteins are all glycosulphohydrolases, involved with desulphatation o f sulphated polysaccharides.