Resistance towards known antimalarial drugs poses a significant problem, urging for novel drugs that target vital proteins in the malaria parasite Plasmodium falciparum. However, recombinant production of malaria proteins is notoriously difficult. To address this, we have investigated two putative K+ channels, PfKch1 and PfKch2, identified in the P. falciparum genome. We show that PfKch1 and PfKch2 and a C-terminally truncated version of PfKch1 (PfKch11−1094) could indeed be functionally expressed in vivo, since a K+-uptake deficient Saccharomyces cerevisiae strain was complemented by the P. falciparum cDNAs. PfKch11−1094-GFP and GFP-PfKch2 fusion proteins were overexpressed in yeast, purified and reconstituted in lipid bilayers to determine their electrophysiological activity. Single channel conductance amounted to 16 ± 1 pS for PfKch11−1094-GFP and 28 ± 2 pS for GFP-PfKch2. We predicted regulator of K+-conductance (RCK) domains in the C-terminals of both channels, and we accordingly measured channel activity in the presence of Ca2+.

中文翻译：

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酿酒酵母中产生的恶性疟原虫K +通道，PfKch1和PfKch2的纯化和初步表征。

对已知抗疟疾药物的耐药性提出了一个重大问题，促使人们开发针对疟疾寄生虫恶性疟原虫中重要蛋白质的新型药物。然而，众所周知，疟疾蛋白的重组生产是困难的。为了解决这个问题，我们研究了恶性疟原虫基因组中鉴定出的两个推定的K +通道PfKch1和PfKch2。我们显示PfKch1和PfKch2以及PfKch1的C末端截短版本（PfKch11−1094）实际上可以在体内表达，因为K +摄取不足的酿酒酵母菌株被恶性疟原虫cDNA所补充。PfKch11−1094-GFP和GFP-PfKch2融合蛋白在酵母中过表达，纯化并在脂质双层中重构，以确定其电生理活性。对于PfKch11−1094-GFP，单通道电导总计为16±1 pS，对于GFP-PfKch2，单通道电导总计为28±2 pS。我们预测了两个通道C末端的K +电导（RCK）域调节剂，因此我们在存在Ca2 +的情况下测量了通道活性。