Howard R F
Agouron Institute, La Jolla, CA.
Mol Biochem Parasitol. 1990 Sep-Oct;42(2):235-40. doi: 10.1016/0166-6851(90)90166-j.
The gene for the Plasmodium falciparum glycolytic enzyme aldolase (PfA) has been cloned. Since polyclonal antibodies raised to an affinity-purified preparation of an approximately 41-kDa parasite rhoptry protein were used to isolate this clone, and its nucleotide sequence was verified using amino acid sequence information generated from the purified 41-kDa protein, the authors concluded that this rhoptry protein was PfA. In the present report, monoclonal antibodies which immunoprecipitate those rhoptry protein complexes containing 39-kDa (p39) and 37-kDa proteins (p37) were used along with PfA-specific polyclonal antibodies to further examine this conclusion. The electrophoretic mobilities of PfA and the rhoptry proteins in the presence of sodium dodecyl sulfate differed from each other in both reducing and nonreducing conditions after immunoprecipitation with these antibodies. Lysates of P. falciparum-infected erythrocytes contained abundant aldolase activity which was removed by anti-PfA antibodies. However, no aldolase activity was associated with affinity-purified rhoptry proteins. Controlled proteolysis with the endoproteinase V8 protease generated different digestion patterns for PfA, p39, and p37. While both PfA and the rhoptry proteins were components of multimeric protein complexes, as demonstrated by sucrose gradient centrifugation, their cellular localization patterns were quite different. These results demonstrate that PfA and the rhoptry-associated proteins p39 and p37 are different entities.
恶性疟原虫糖酵解酶醛缩酶（PfA）的基因已被克隆。由于用于分离该克隆的多克隆抗体是针对一种亲和纯化的约41 kDa寄生虫棒状体蛋白制备的，并且其核苷酸序列是利用从纯化的41 kDa蛋白产生的氨基酸序列信息进行验证的，作者得出结论，这种棒状体蛋白就是PfA。在本报告中，使用能免疫沉淀那些含有39 kDa（p39）和37 kDa蛋白（p37）的棒状体蛋白复合物的单克隆抗体，以及PfA特异性多克隆抗体，来进一步检验这一结论。在用这些抗体进行免疫沉淀后，在还原和非还原条件下，PfA和棒状体蛋白在十二烷基硫酸钠存在下的电泳迁移率彼此不同。恶性疟原虫感染的红细胞裂解物含有丰富的醛缩酶活性，该活性可被抗PfA抗体去除。然而，亲和纯化的棒状体蛋白未显示有醛缩酶活性。用内蛋白酶V8蛋白酶进行的可控蛋白水解对PfA、p39和p37产生了不同的消化模式。正如蔗糖梯度离心所显示的，虽然PfA和棒状体蛋白都是多聚体蛋白复合物的组成成分，但它们的细胞定位模式却大不相同。这些结果表明，PfA与棒状体相关蛋白p39和p37是不同的实体。
