Species-specific aggregation factor in sponges XIII. Entire and core structure of the large circular proteid particle from Geodia cydonium

Abstract

High-molecular weight particles have been isolated from the sponge Geodica cydonium. In the ‘native’ form these particles consist of a spherical center and have 25–30 filaments attached to it. The core structure of the particles is assembled of a central circle and 25 radially-arranged filaments. The core structure is obtained from the entire structure by incubation in a medium, containing a non-ionic detergent and EDTA. The molecular weight of the entire structure was in the range of 1.4 × 10 9 daltons or more and of the core structure 6.1 × 10 8 daltons. Two functional proteins are released from the ‘native’ particles: the aggregation factor and the sialyltransferase.