Da Silva E, Foley M, Dluzewski A R, Murray L J, Anders R F, Tilley L
Department of Biochemistry, La Trobe University, Bundoora, Victoria, Australia.
Mol Biochem Parasitol. 1994 Jul;66(1):59-69. doi: 10.1016/0166-6851(94)90036-1.
The ring-infected erythrocyte surface antigen (RESA) associates with spectrin in the erythrocyte membrane (Foley, M., Tilley, L., Sawyer, W. H. and Anders, R. F. (1991) Mol. Biochem. Parasitol., 46, 137-148). A fragment of the RESA protein, which was expressed in Escherichia coli, was found to bind to inside-out vesicles of erythrocyte membranes in an apparently saturable manner. Upon extraction of inside-out vesicles with Triton X-100, the RESA fragment remained associated with the erythrocyte cytoskeleton. Using the technique of steady-state fluorescence polarisation, we have studied the thermal denaturation of fluorescein-labelled spectrin in the presence of recombinant RESA. We found that the RESA fragment partially protected spectrin against heat-induced conformational changes. Furthermore, erythrocytes infected with a RESA (-) laboratory strain (FCR3) were shown to be more susceptible to heat-induced fragmentation than erythrocytes infected with a RESA (+) strain of the parasite. RESA does not, however, appear to play an essential role in the invasion process per se as erythrocytes resealed to contain anti-RESA antibodies were efficiently invaded.
环感染红细胞表面抗原（RESA）与红细胞膜中的血影蛋白相关联（Foley, M., Tilley, L., Sawyer, W. H. 和 Anders, R. F. (1991) Mol. Biochem. Parasitol., 46, 137 - 148）。在大肠杆菌中表达的RESA蛋白片段，被发现以一种明显可饱和的方式与红细胞膜的外翻小泡结合。用Triton X - 100提取外翻小泡后，RESA片段仍与红细胞细胞骨架相关联。利用稳态荧光偏振技术，我们研究了在重组RESA存在下荧光素标记血影蛋白的热变性。我们发现RESA片段部分保护血影蛋白免受热诱导的构象变化影响。此外，与感染了寄生虫RESA（+）菌株的红细胞相比，感染了RESA（-）实验室菌株（FCR3）的红细胞对热诱导的破碎更敏感。然而，RESA似乎在入侵过程本身中并不起关键作用，因为重新封闭以含有抗RESA抗体的红细胞仍能被有效入侵。
