CLONING AND EXPRESSION OF THE THROMBOSPONDIN RELATED ADHESIVE PROTEINGENE OF PLASMODIUM-BERGHEI

Sporozoite recognition of host cells is a key step in the life-cycle o f malaria parasites. Two sporozoite proteins have so far been characte rized in some detail, the circumsporozoite protein (CS) and thrombospo ndin related adhesive protein (TRAP). We report here the cloning and e xpression of the TRAP gene homologue from Plasmodium berghei, PbTRAP. The PbTRAP gene encodes a protein of 606 amino acids having a deduced molecular mass of 66 kDa. The overall structure is clearly that of the TRAP family having a signal sequence followed by an integrin A domain , a sulphatide binding motif, followed by a proline based repeat befor e a transmembrane domain and helical cytoplasmic tail. The observed mo lecular mass is almost 50% larger than expected, this can be explained almost entirely by the abnormal behaviour in SDS-PAGE of the proline based repeat. As would be expected PbTRAP shows greatest similarity wi th the P. falciparum TRAP homologue sporozoite surface protein 2 (SSP2 ) than with PfTRAP, the TRAP gene from P. falciparum. The pattern of e xpression is similar to that of SSP2. Copyright (C) 1997 Elsevier Scie nce B.V.