首页> 外文OA文献 >Identification of a putative glycosyltransferase responsible for the transfer of pseudaminic acid onto the polar flagellin of Aeromonas caviae Sch3N
【2h】

Identification of a putative glycosyltransferase responsible for the transfer of pseudaminic acid onto the polar flagellin of Aeromonas caviae Sch3N

机译:鉴定一个假定的糖基转移酶,负责将伪氨基酸转移到豚鼠气单胞菌Sch3N的极性鞭毛蛋白上

代理获取
本网站仅为用户提供外文OA文献查询和代理获取服务,本网站没有原文。下单后我们将采用程序或人工为您竭诚获取高质量的原文,但由于OA文献来源多样且变更频繁,仍可能出现获取不到、文献不完整或与标题不符等情况,如果获取不到我们将提供退款服务。请知悉。

摘要

Motility in Aeromonas caviae, in a liquid environment (in broth culture), is mediated by a single polar flagellum encoded by the fla genes. The polar flagellum filament of A. caviae is composed of two flagellin subunits, FlaA and FlaB, which undergo O-linked glycosylation with six to eight pseudaminic acid glycans linked to serine and threonine residues in their central region. The flm genetic locus in A. caviae is required for flagellin glycosylation and the addition of pseudaminic acid (Pse) onto the lipopolysaccharide (LPS) O-antigen. However, none of the flm genes appear to encode a candidate glycotransferase that might add the Pse moiety to FlaA/B. The motility-associated factors (Maf proteins) are considered as candidate transferase enzymes, largely due to their conserved proximity to flagellar biosynthesis loci in a number of pathogens. Bioinformatic analysis performed in this study indicated that the genome of A. caviae encodes a single maf gene homologue (maf1). A maf mutant was generated and phenotypic analysis showed it is both nonmotile and lacks polar flagella. In contrast to flm mutants, it had no effect on the LPS O-antigen pattern and has the ability to swarm. Analysis of flaA transcription by reverse transcriptase PCR (RT-PCR) showed that its transcription was unaltered in the maf mutant while a His-tagged version of the FlaA flagellin protein produced from a plasmid was detected in an unglycosylated intracellular form in the maf strain. Complementation of the maf strain in trans partially restored motility, but increased levels of glycosylated flagellin to above wild-type levels. Overexpression of maf inhibited motility, indicating a dominant negative effect, possibly caused by high amounts of glycosylated flagellin inhibiting assembly of the flagellum. These data provide evidence that maf1, a pseudaminyl transferase, is responsible for glycosylation of flagellin and suggest that this event occurs prior to secretion through the flagellar Type III secretion system.
机译:在液体环境中(在肉汤培养中),豚鼠气单胞菌的运动性由fla基因编码的单个极性鞭毛介导。豚鼠杆状鞭毛细丝由两个鞭毛蛋白亚基FlaA和FlaB组成,它们的O-链糖基化与中心区域的丝氨酸和苏氨酸残基相连的六到八个假氨基酸多糖。鞭毛蛋白糖基化和在脂多糖(LPS)O抗原上添加伪氨基酸(Pse)都需要ca.caviae的flm遗传基因座。但是,flm基因似乎均未编码可能将Pse部分添加至FlaA / B的候选糖基转移酶。与运动相关的因子(Maf蛋白)被认为是候选转移酶,主要是由于它们在许多病原体中与鞭毛生物合成基因座的保守距离。在这项研究中进行的生物信息学分析表明,曲霉的基因组编码一个单一的maf基因同源物(maf1)。产生了maf突变体,表型分析表明该突变体既不运动也不缺乏极鞭毛。与flm突变体相反,它对LPS O抗原模式没有影响,并且具有蜂群的能力。通过逆转录酶PCR(RT-PCR)分析flaA转录显示,其转录在maf突变体中未改变,而在maf菌株中以未糖基化的细胞内形式检测到了由质粒产生的FlaA鞭毛蛋白的His标记版本。反式maf品系的补充部分恢复了活力,但糖基化鞭毛蛋白的水平增加至野生型水平。黑手党的过表达抑制了运动,表明主要的负面影响,可能是由于大量糖基化鞭毛抑制鞭毛的组装所致。这些数据提供了证据,即伪氨基转移酶maf1负责鞭毛蛋白的糖基化,并表明该事件发生在通过鞭毛III型分泌系统分泌之前。

著录项

相似文献

  • 外文文献
  • 专利
代理获取

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号