B. Kappes et al., 2 MAJOR PHOSPHOPROTEINS OF PLASMODIUM-FALCIPARUM ARE HEAT-SHOCK PROTEINS, Molecular and biochemical parasitology, 59(1), 1993, pp. 83-94
Two major phosphoproteins of Plasmodium falciparum could be identified
by partial amino acid sequencing as the plasmodial members of the hsp
70 heat shock protein family, Pfhsp and Pfgrp. According to phosphoam
ino acid analyses of Pfhsp and Pfgrp isolated from [P-32]orthophosphat
e-labeled malarial cultures, both proteins were phosphorylated in Ser
and Thr. While Pfhsp contains higher amounts of labeled phosphoserine,
Pfgrp contains higher amounts of phosphothreonine. Phosphorylation of
both proteins increased throughout the entire erythrocytic growth cyc
le. At the trophozoite and schizont stages Pfhsp and Pfgrp are the mos
t prominant phosphoproteins of Plasmodium falciparum. Using multiply r
edundant oligonucleotides directed against the N-terminus of Pfgrp we
cloned and sequenced the entire Pfgrp gene. The gene encodes a product
with a predicted length of 652 amino acids. The deduced amino acid se
quence has identities of 65.5% and 65.0% to the human and rat grp78 pr
oteins, respectively. Pfgrp possesses a classical N-terminal leader se
quence. The published grp78 related gene sequences of Plasmodium falci
parum are all fragments of the same plasmodial gene.