Hada Kazumasa, Nakashima Takashi, Osawa Takuo, Shimada Hiroaki, Kakuta Yoshimitsu, Kimura Makoto
Laboratory of Structural Biology, Graduate School of Systems Life Sciences, Kyushu University, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
Biosci Biotechnol Biochem. 2008 Mar;72(3):749-58. doi: 10.1271/bbb.70639. Epub 2008 Mar 7.
The crystal structure of the Alba protein (PhoAlba) from a hyperthermophilic archaeon, Pyrococcus horikoshii OT3, was determined at a resolution of 2.8 A. PhoAlba structurally belongs to the alpha/beta proteins and is similar not only to archaeal homologues but also to RNA-binding proteins, including the C-terminal half of initiation factor 3 (IF3-C) from Bacillus stearothermophilus, an Esherichia coli protein implicated in cell division (Yhhp), and an Arabidopsis protein of unknown function. We found by gel shift assay that PhoAlba interacts with both ribonuclease P (RNase P) RNA (PhopRNA) and precursor-tRNA(Tyr) (pre-tRNA(Tyr)) in P. horikoshii. However, the addition of PhoAlba to reconstituted particles composed of PhopRNA and four or five protein subunits had little influence on either the pre-tRNA processing activity or the optimum temperature for the processing activity. These results suggest that PhoAlba contributes little to the catalytic activity of P. horikoshii RNase P.
嗜热古菌火烈鸟栖热球菌OT3（Pyrococcus horikoshii OT3）的Alba蛋白（PhoAlba）的晶体结构以2.8埃的分辨率测定。PhoAlba在结构上属于α/β蛋白，不仅与古菌同源物相似，而且与RNA结合蛋白相似，包括嗜热脂肪芽孢杆菌起始因子3的C端一半（IF3-C）、一种与大肠杆菌细胞分裂有关的蛋白（Yhhp）以及一种功能未知的拟南芥蛋白。我们通过凝胶迁移试验发现，PhoAlba与火烈鸟栖热球菌中的核糖核酸酶P（RNase P）RNA（PhopRNA）和前体tRNA（Tyr）（pre-tRNA（Tyr））都相互作用。然而，将PhoAlba添加到由PhopRNA和四个或五个蛋白质亚基组成的重组颗粒中，对前体tRNA加工活性或加工活性的最适温度几乎没有影响。这些结果表明，PhoAlba对火烈鸟栖热球菌RNase P的催化活性贡献不大。
