Biochemical characterization of FIKK8--A unique protein kinase from the malaria parasite Plasmodium falciparum and other apicomplexans.
Biochemical characterization of FIKK8--A unique protein kinase from the malaria parasite Plasmodium falciparum and other apicomplexans.
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DOI：
10.1016/j.molbiopara.2015.06.002
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发表时间：
2015-06
影响因子：
1.5
通讯作者：
Hui R
中科院分区：
文献类型：
--
作者：
Osman KT;Lou HJ;Qiu W;Brand V;Edwards AM;Turk BE;Hui R
我们研究了来自恶性疟原虫和隐孢子虫的FIKK激酶。PfFIKK 8和CpFIKK的可溶性和活性样品含有N-末端延伸。两种FIKK样品都优先磷酸化具有侧翼丝氨酸的丝氨酸。FIKK是具有独特序列基序的蛋白激酶，仅在顶复门中发现。在这里，我们报告恶性疟原虫FIKK 8（PfFIKK 8）和它的隐孢子虫parvum直向同源物（CpFIKK）的生化特性-唯一的成员预测是胞质和保守的家庭之间的非疟原虫寄生虫。两者的重组蛋白样品具有催化活性。我们的特点是他们的磷酸化能力，使用酶法和底物特异性，使用阵列位置扫描肽库。我们的研究结果表明，FIKK 8靶向丝氨酸，最好在+3和-3位置与精氨酸。此外，我们实验中的可溶性和活性FIKK构建体含有在来自其他顶复门物种的FIKK 8直系同源物中保守的N-末端延伸（NTE）。基于我们的研究结果，我们建议，这NTE是一个不可分割的功能的FIKK子家族。
We studied FIKK kinases from Plasmodium falciparum and Cryptosporidium parvum. Soluble and active samples of PfFIKK8 and CpFIKK contain a N-terminal extension. Both FIKK samples preferentially phosphorylated serines with flanking arginines. FIKKs are protein kinases with distinctive sequence motifs found exclusively in Apicomplexa. Here, we report on the biochemical characterization of Plasmodium falciparum FIKK8 (PfFIKK8) and its Cryptosporidium parvum orthologue (CpFIKK) – the only member of the family predicted to be cytosolic and conserved amongst non-Plasmodium parasites. Recombinant protein samples of both were catalytically active. We characterized their phosphorylation ability using an enzymatic assay and substrate specificities using an arrayed positional scanning peptide library. Our results show that FIKK8 targets serine, preferably with arginine in the +3 and −3 positions. Furthermore, the soluble and active FIKK constructs in our experiments contained an N-terminal extension (NTE) conserved in FIKK8 orthologues from other apicomplexan species. Based on our results, we propose that this NTE is an integral feature of the FIKK subfamily.