Malaria Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi-110067, India.
Gene. 2013 Feb 15;515(1):99-109. doi: 10.1016/j.gene.2012.11.020. Epub 2012 Dec 2.
RuvB family of protein contains two similar kinds of proteins i.e. RuvB1 and RuvB2 from yeast to human. These proteins belong to the AAA+ class of proteins and are critical components of several multiprotein complexes involved in diverse cellular activities. There are two RuvB proteins annotated in the Plasmodium database but the identification of the third protein recently by our lab has raised the question why Plasmodium falciparum contains three RuvB proteins instead of two. Hence the biochemical characterizations of these proteins have become essential to understand the role of these proteins in the malaria parasite. Recently we have reported the characterization of the recombinant PfRuvB3, which contains ATPase activity but lacks DNA helicase activity. In the present study we report the phylogenetic analysis and detailed biochemical characterization of one of the other RuvB homologue RuvB1 from P. falciparum. PfRuvB1 shows considerable homology with human as well as yeast RuvB1 and contains Walker motif A and Walker motif B. The activity analysis of this protein revealed that PfRuvB1 is an ATPase and this activity increased significantly in the presence of ss-DNA. PfRuvB1 also contains DNA helicase activity and translocates preferentially in 5' to 3' direction. In vivo investigation of PfRuvB1 revealed that it is constitutively expressed during all the stages of intraerythrocytic cycle of P. falciparum and localizes mainly to the nucleus. These studies will make important contribution in understanding the role of RuvB protein in P. falciparum.
RuvB 家族蛋白包含两种类似的蛋白，即酵母到人类的 RuvB1 和 RuvB2。这些蛋白属于 AAA+ 蛋白家族，是参与多种细胞活动的多个多蛋白复合物的关键组成部分。在疟原虫数据库中有两种 RuvB 蛋白被注释，但我们实验室最近鉴定的第三种蛋白提出了一个问题，即恶性疟原虫为什么含有三种而不是两种 RuvB 蛋白。因此，这些蛋白的生化特性的研究对于理解这些蛋白在疟原虫中的作用变得至关重要。最近，我们报道了重组 PfRuvB3 的特性，它具有 ATP 酶活性，但缺乏 DNA 解旋酶活性。在本研究中，我们报告了另一种 RuvB 同源物 PfRuvB1 的系统发育分析和详细的生化特性。PfRuvB1 与人类和酵母 RuvB1 具有相当大的同源性，并且包含 Walker 基序 A 和 Walker 基序 B。该蛋白的活性分析表明 PfRuvB1 是一种 ATP 酶，并且在 ss-DNA 存在下其活性显著增加。PfRuvB1 还含有 DNA 解旋酶活性，并优先向 5'到 3'方向迁移。PfRuvB1 的体内研究表明，它在恶性疟原虫的整个红细胞内周期的所有阶段都持续表达，并主要定位于核内。这些研究将对理解 RuvB 蛋白在恶性疟原虫中的作用做出重要贡献。
