Purification and partial characterization of an actin-like protein from cricket early egg plasmodium

The purification of an actin-like protein from cricket egg yolk plasmodia by different selective extraction procedures, ammonium sulphate precipitation, ion exchange and immunoabsorption chromatography is described. Criteria of purity from analytical ultracentrifugation, SDS-disc electrophoresis, and immunoelectrophoresis are presented. Immunodiffusion analysis was used to control the success of the purification procedures.The molecular weight of the monomeric form is 60000±10%. Polymerization to pearl-chain aggregate structures occurs under different conditions in 0.1 M KCl in the presence of ATP. Vinblastine precipitation leads to similar structures. Possibly related structures and the possible rÔle of this protein in organizing movements in the plasmodial system are discussed.