应用计算机手段分析植物病原细菌Ralstonia solanacearum的蛋白质序列*

 应用SignalP 3.0，LipoP和TargetP对植物病原细菌Ralstonia solanacearum基因组中的3440个ORFs（open reading frames）进行了信号肽分析，同时系统分析了信号肽的类型及结构。结果表明，3440个ORFs中有462个ORFs所编码蛋白质具有N-端有信号肽序列，其中348个分泌类信号肽、100个信号肽具有RR-motif信号肽，14个脂蛋白类信号肽，未发现Prepilin-like 信号肽和Bacteriocin and Pheromone信号肽。在这462个具有可切割信号肽的分泌蛋白中，有84.0%蛋白质为胞外分泌型（S型），13.2%为线粒体分泌型（M型），另外有2.8%为其它类型的分泌蛋白。通过LipoP分析该菌的全基因组预测具有4种类型蛋白质，其中其中SpI有425个，占12.3%；SpII有80个，占2.3%；CYT有2541个，占73.9%；TMH有414个，占12.0%。比较了Ralstonia solanacearum和Pseudomonas syringae pv. tomato信号肽的长度及氨基酸的组成，发现这两种菌在这些方面存在这很大程度的相似性。本研究通过对Ralstonia solanacearum进行分泌蛋白和信号肽结构的分析，为将来功能基因组和分泌型外源蛋白的利用提供理论基础。

Computational Analysis of Protein Sequences in Ralstonia solanacearum

Analysis of the completed set of 3 440 ORFs in whole genomic sequence of chromosome of Ralstonia solanacearum by SignalP 3.0, LipoP and TargetP revealed that 462 ORFs consist of putative secretory proteins with signal peptides.This includes members of the three major classes of signal peptides: 348 secretory signal peptides,100 twin-arginine signal peptides,14 lipoprotein signal peptides,and absent of Prepilin-like and Bacteriocin & Pheromone signal peptides.The subcellular localization predicted by TargetP reveals that 3 groups in 462 secretory proteins: e.g.mitochondrion(M),secretory pathway(S) and other location.There are 4 types consist of 12.3% SpI(signal peptide),2.3% SpII(lipoprotein signal peptide,73.9% CYT(cytoplasmic) and 12.0% TMH(N-terminal transmembrane helix) by LipoP in genome of the strain.Compared with the length and amino acid composition of most signal peptides between Ralstonia solanacearum and Pseudomonas syringae pv.tomato,it revealed there were similarities on the two bacteria.