Department of Cell and Molecular Biology, University of Gothenburg, Göteborg, Sweden.
RNA Biol. 2009 Nov-Dec;6(5):508-16. doi: 10.4161/rna.6.5.9753. Epub 2009 Nov 7.
The signal recognition particle (SRP) is a ribonucleoprotein complex which participates in the targeting of protein to cellular membranes. The RNA component of the SRP has been found in all domains of life, but the size of the molecule and the number of RNA secondary structure elements vary considerably between the different phylogenetic groups. We continued our efforts to identify new SRP RNAs, compare their sequences, discover new secondary structure elements, conserved motifs, and other properties. We found additional proof for the variability in the apical loop of helix 8, and we identified several bacteria which lack all of their SRP components. Based on the distribution of SRP RNA features within the taxonomy, we suggest seven alignment groups: Bacteria with a small (4.5S) SRP RNA, Bacteria with a large (6S) SRP RNA, Archaea, Fungi (Ascomycota), Metazoa group, Protozoa group, and Plants. The proposed divisions improve the prediction of more distantly related SRP RNAs and provide a more inclusive representation of the SRP RNA family. Updates of the Rfam SRP RNA sequence collection are expected to benefit from the suggested groupings.
信号识别颗粒 (SRP) 是一种参与蛋白质靶向到细胞膜的核糖核蛋白复合物。SRP 的 RNA 成分存在于所有生命领域，但不同进化群之间的分子大小和 RNA 二级结构元件数量差异很大。我们继续努力识别新的 SRP RNA，比较它们的序列，发现新的二级结构元件、保守基序和其他特性。我们发现了更多关于螺旋 8 顶端环变异性的证据，并且鉴定出一些缺乏所有 SRP 成分的细菌。基于 SRP RNA 特征在分类学中的分布，我们建议了七个对齐组：具有小（4.5S）SRP RNA 的细菌、具有大（6S）SRP RNA 的细菌、古菌、真菌（子囊菌）、后生动物组、原生动物组和植物。所提出的划分改进了对更远缘 SRP RNA 的预测，并提供了更具包容性的 SRP RNA 家族代表。预期建议的分组将使 Rfam SRP RNA 序列集合的更新受益。
