Brown Eric D
Antimicrobial Research Centre and Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON, Canada.
Biochem Cell Biol. 2005 Dec;83(6):738-46. doi: 10.1139/o05-162.
Establishing the roles of conserved gene products in bacteria is of fundamental importance to our understanding of the core protein complement necessary to sustain cellular life. P-loop GTPases and related ATPases represent an abundant and remarkable group of proteins in bacteria that, in many cases, have evaded characterization. Here, efforts aimed at understanding the cellular function of a group of 8 conserved, poorly characterized genes encoding P-loop GTPases, era, obg, trmE, yjeQ, engA, yihA, hflX, ychF, and a related ATPase, yjeE, are reviewed in considerable detail. While concrete cellular roles remain elusive for all of these genes and considerable pleiotropy has plagued their study, experiments to date have frequently implicated the ribosome. In the case of era, obg, yjeQ, and engA, the evidence is most consistent with roles in ribosome biogenesis, though the prediction is necessarily putative. While the protein encoded in trmE clearly has a catalytic function in tRNA modification, the participation of its GTPase domain remains obscure, as do the functions of the remaining proteins. A full understanding of the cellular functions of all of these important proteins remains the goal of ongoing studies of cellular phenotype and protein biochemistry.
确定保守基因产物在细菌中的作用对于我们理解维持细胞生命所必需的核心蛋白质组成至关重要。P环GTP酶和相关ATP酶是细菌中一类丰富且引人注目的蛋白质，在许多情况下，它们尚未得到充分表征。本文详细综述了旨在了解一组8个保守的、表征不佳的编码P环GTP酶的基因（era、obg、trmE、yjeQ、engA、yihA、hflX、ychF）以及一个相关ATP酶yjeE的细胞功能的研究工作。尽管所有这些基因的具体细胞作用仍不明确，且显著的多效性一直困扰着对它们的研究，但迄今为止的实验经常涉及核糖体。就era、obg、yjeQ和engA而言，证据最支持它们在核糖体生物合成中的作用，不过这一推测必然具有一定的不确定性。虽然trmE编码的蛋白质在tRNA修饰中显然具有催化功能，但其GTP酶结构域的作用仍不清楚，其余蛋白质的功能也是如此。全面了解所有这些重要蛋白质的细胞功能仍然是当前细胞表型和蛋白质生物化学研究的目标。
