Riekenberg S, Witjes B, Sarić M, Bruchhaus I, Scholze H
Department of Biology/Chemistry, University of Osnabrueck, 49069 Osnabrueck, Germany.
FEBS Lett. 2005 Mar 14;579(7):1573-8. doi: 10.1016/j.febslet.2005.01.067.
Based on the Entamoeba histolytica genome project (www.sanger.ac.uk/Project/E_histolytical/) we have identified a cysteine protease inhibitor, EhICP1 (amoebiasin 1), with significant homology to chagasin. Recombinant EhICP1 inhibited the protease activity of papain and that of a trophozoite lysate with Ki's in the picomolar range. By immunocytology, we localized the endogenous approximately 13 kDa EhICP1 in a finely dotted subcellular distribution discrete from the vesicles containing the amoebic cysteine protease, EhCP1 (amoebapain). In an overlay assay, we observed binding of recombinant EhICP1 to EhCP1. As a heptapeptide (GNPTTGF) corresponding to the second conserved chagasin motif inhibited the protease activity of both papain (K) 1.5 microM) and trophozoite extract (Ki in sub-mM range), it may be a candidate for the rational development of anti-amoebiasis drugs.
基于溶组织内阿米巴基因组计划（www.sanger.ac.uk/Project/E_histolytical/），我们鉴定出一种半胱氨酸蛋白酶抑制剂EhICP1（阿米巴素1），它与查加辛具有显著同源性。重组EhICP1抑制木瓜蛋白酶和滋养体裂解物的蛋白酶活性，其抑制常数（Ki）在皮摩尔范围内。通过免疫细胞化学，我们将内源性约13 kDa的EhICP1定位在一种精细点状的亚细胞分布中，与含有阿米巴半胱氨酸蛋白酶EhCP1（阿米巴蛋白酶）的囊泡不同。在覆盖试验中，我们观察到重组EhICP1与EhCP1结合。由于对应于查加辛第二个保守基序的七肽（GNPTTGF）抑制木瓜蛋白酶（Ki 1.5 microM）和滋养体提取物（Ki在亚毫摩尔范围内）的蛋白酶活性，它可能是合理开发抗阿米巴病药物的候选物。
