Identification and purification of a soluble species of gp120 released by zymolyase treatment of Pneumocystis carinii.

Purified zymolyase containing beta-glucanase activity releases a soluble species of the gp120 component of the high molecular weight surface antigen complex of rat- and human-derived Pneumocystis carinii. We have purified the soluble gp120 from rat-derived P. carinii by concanavalin A-affinity- and hydrophobic-interaction liquid chromatography. A single band was detected in this fraction by silver staining and immunoblotting. We have also partially purified a soluble form of the corresponding high molecular weight surface antigen from human-derived P. carinii. Identification and purification of a nondenatured soluble species of gp120 will assist in the characterization of its interactions within the surface antigen complex and with host molecules.