Morrison Hilary G, Zamora Gus, Campbell Robert K, Sogin Mitchell L
Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, 7 MBL Street, Woods Hole, MA 02543-1015, USA.
Comp Biochem Physiol B Biochem Mol Biol. 2002 Dec;133(4):477-91. doi: 10.1016/s1096-4959(02)00218-x.
Functional assays of genes have historically led to insights about the activities of a protein or protein cascade. However, the rapid expansion of genomic and proteomic information for a variety of diverse taxa is an alternative and powerful means of predicting function by comparing the enzymes and metabolic pathways used by different organisms. As part of the Giardia lamblia genome sequencing project, we routinely survey the complement of predicted proteins and compare those found in this putatively early diverging eukaryote with those of prokaryotes and more recently evolved eukaryotic lineages. Such comparisons reveal the minimal composition of conserved metabolic pathways, suggest which proteins may have been acquired by lateral transfer, and, by their absence, hint at functions lost in the transition from a free-living to a parasitic lifestyle. Here, we describe the use of bioinformatic approaches to investigate the complement and conservation of proteins in Giardia involved in the regulation of translation. We compare an FK506 binding protein homologue and phosphatidylinositol kinase-related kinase present in Giardia to those found in other eukaryotes for which complete genomic sequence data are available. Our investigation of the Giardia genome suggests that PIK-related kinases are of ancient origin and are highly conserved.
从历史上看，基因功能分析有助于深入了解蛋白质或蛋白质级联反应的活性。然而，各种不同分类群的基因组和蛋白质组信息的迅速扩展，是通过比较不同生物体所使用的酶和代谢途径来预测功能的一种强大的替代方法。作为贾第虫基因组测序项目的一部分，我们定期调查预测蛋白质的组成，并将在这种推测为早期分化的真核生物中发现的蛋白质与原核生物以及最近进化的真核生物谱系中的蛋白质进行比较。这样的比较揭示了保守代谢途径的最小组成，表明哪些蛋白质可能是通过横向转移获得的，并且通过它们的缺失暗示了在从自由生活向寄生生活方式转变过程中丧失的功能。在这里，我们描述了使用生物信息学方法来研究贾第虫中参与翻译调控的蛋白质的组成和保守性。我们将贾第虫中存在的一种FK506结合蛋白同源物和磷脂酰肌醇激酶相关激酶与在其他有完整基因组序列数据的真核生物中发现的进行比较。我们对贾第虫基因组的研究表明，PIK相关激酶起源古老且高度保守。
