Hemoxidation and binding of the 46-kDa cystalysin of Treponema denticola leads to a cysteine-dependent hemolysis of human erythrocytes

Cystalysin, a 46-kDa protein isolated from the cytosol of Treponema dentico la, was capable of both cysteine dependent hemoxidation and hemolysis of hu man and sheep red blood cells. The activities were characteristic of a cyst eine desulfhydrase. Sodium dodecyl sulfate-polyacrylamide gel electrophores is (SDS-PAGE) and Western immunoblotting analysis of the interaction of cys talysin with the red blood cells revealed an interaction of the protein wit h the red blood cell membrane. Substrates for the enzyme (including L-cyste ine and beta-chloroalanine) enhanced the interaction, which occurred with b oth whole red blood cells as well as with isolated and purified red blood c ell ghosts. SDS-PAGE and western immunoblotting employing anti-hemoglobin s erum revealed that, during the hemoxidative events, the hemoglobin molecule associated with the red blood cell membrane, forming putative Heinz bodies . Spectrophotometric analysis of the hemoxidative events (cystalysin + cyst eine + red blood cells) revealed a chemical modification of the native hemo globin to sulfhemoglobin and methemoglobin, Hemoxidation also resulted in t he degradation of both the red blood cell alpha- and beta-spectrin. The res ults presented suggest that the interaction of cystalysin with the red bloo d cell membrane results in the chemical oxidation of the hemoglobin molecul e as well as an alteration in the red blood cell membrane itself.