摘要
蛋白质O-甘露糖基化是一种广泛存在于生物体内的蛋白质翻译后修饰过程,即在Dol-P甘露糖转移酶(PMT)催化下将长萜酰甘露糖上的甘露糖连接到肽链上丝氨酸或者苏氨酸羟基的过程。本文对国际千种植物转录组计划(1KP)中22种海洋红藻及19种海洋褐藻的转录组数据库进行搜索,获得了6条来自海萝(Gloiopeltis furcata)的PMT基因序列。通过对其序列特征的分析发现藻类PMT序列与真菌及动物具有相似的亲疏水性列谱,表明真核生物PMT间具有相似的跨膜区。藻类PMT的N端较为保守,但较其他真核生物PMT的loop5存在222个氨基酸的缺失,导致其loop5处缺少了3个MIR结构域使得loop5明显减小。此外,利用贝叶斯法构建系统进化树表明藻类的PMT基因来自于内共生过程的质体基因转移。
Protein O-mannosylation is an extensive posttranslational modification.This reaction is catalyzed by a family of dolichyl-phosphate-mannose-protein mannosyltransferase(PMT),starts with the transfer of mannose from dolichyl mannose to seryl or threonyl residues of secretory proteins.As part of the 1 000 Plant Project(1KP),we provided marine macroalgal transcriptome of 22 red species and 19 brown species from China.In this study,the transcriptome database of 22 red algae Phaeophyceae and 19 brown algae Phaeophyceae were searched.Six PMTgene copies of Gloiopeltis furcata were obtained from red algae database and none PMTgene was found in the brown algae database.It suggested that brown algae lost PMTgene in their evolutionary process.Then,the analysis of hydropahy profiles suggested that the amino acid sequence of algal PMT had similar hydropahy profiles with the PMT from fungi and animal,indicating that there were similar transmembrane regions among eukaryotes.Compared with other eukaryotes,the N-terminal amino acid sequences of algal PMT were relatively conserved.The Asp-Glu motif in N-terminal of PMT is essential for the formation and stability of PMT complexes.However,the lack of 222 amino acids at loop5 made the algal PMT lose three MIR domains.And the same deletion also happened in bacterial PMT.According to the Bayesian phylogenetic tree,the algal PMTgene was derived from endosymbiont by endosymbiotic gene transfer(EGT).Rhodophyta acquired the PMT gene via cyanobacteria during the primary endosymbiotic event and Haptophyta acquired the PMTgene via red-like endosymbiont during the secondary endosymbiotic event.Later,Gene duplication brought different PMTgene copies.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第2期56-63,共8页
Periodical of Ocean University of China
基金
广东省省级科技计划项目(2013B021100008)
青岛市应用基础研究计划项目(14-2-4-102-jch)
青岛创业创新领军人才计划项目资助~~
