保存的C-终端尾部负责 Pseudomonas aeruginosa 血红的膜定位和功能
Stacie Stuut Balsam1, Fangfang Zhong2, Natasha Pence2
1Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, United States.
Biochemistry
|July 1, 2024
概括
Pseudomonas aeruginosa hemerythrin (Mhr) 的 C-终端尾部在微氧时对膜结合和细菌适应性至关重要. 这个尾巴指导Mhrhr.
科学领域:
- 微生物学 微生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 血红素 (Hr) 蛋白在许多细菌中结合O2,在Pseudomonas aeruginosa中由微氧诱导的Hr (Mhr) 赋予了健身优势.
- 与其他Hrs相比,Mhr具有独特的C-终端延伸,在马蛋白细菌中保存,并预测形成螺旋结构.
研究的目的:
- 研究Mhr的C端尾在其定位,功能和与细菌膜相互作用中的作用.
- 阐明在Mhr.中保存的C端残留物的结构和功能意义.
主要方法:
- 细菌细胞分离试验以确定蛋白质局部化.
- 局部定向的突变发生产生Mhr变体 (MhrW143*,MhrL112Y).
- 用脂质囊泡和分子动力学模拟进行光研究.
主要成果:
- 野生类型的Mhr局限于膜和细胞溶液分数,而缺乏C端11残留物的变体 (MhrW143*) 主要是细胞溶液.
- 对于Mhr与脂质囊泡的关联,C端尾是必要的,也是足够的.
- 在尾部保存的负电荷残留物与负电荷膜相互作用,独立于O2结合.
结论:
- 在微氧环境中,Mhr C端尾指导外周膜相互作用,这对于Mhr功能和细菌在微氧环境中的竞争能力至关重要.
- 膜协会通过涉及尾部带电残留物的静电相互作用进行介导.
- 这些发现突显了细菌生理学中由C端域调节的蛋白质膜相互作用的重要性.
相关概念视频
Tail-anchoring of Proteins in the ER Membrane
3.1K
Tail-anchored, or TA, proteins are estimated to make up to 3-5% of membrane proteins found in the eukaryotic cell. Such proteins have a single transmembrane domain located approximately 30 amino acid residues upstream from the C-terminal end. As a result, the signal recognition particle (SRP) cannot guide a TA protein to the ER membrane for cotranslational insertion. Hence, they are integrated into the ER membrane post-translationally using their C-terminal end as the anchor. TA proteins...
3.1K
Insertion of Single-pass Transmembrane Proteins in the RER
6.7K
Integral membrane proteins are proteins adhered to the lipid bilayer of a cell organelle or membrane. They can be of two types: transmembrane integral proteins that span the lipid bilayer and monotopic proteins that are attached to either side of the membrane but do not pass through it.
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
Integral transmembrane proteins possess transmembrane and extra membrane domains. The transmembrane domains are primarily made of 20-25 hydrophobic amino acids arranged in a helical secondary confirmation. These...
6.7K
Lipids as Anchors
5.6K
In the plasma membrane, the lipids forming the bilayer can also act as an anchor to tether proteins to the membrane. The three main types of lipid anchors found in eukaryotes are – prenyl groups, fatty acyl groups, and glycosylphosphatidylinositol or GPI groups. Prenyl and fatty acyl groups act as anchors on the cytosolic surface of the membrane, whereas GPI anchors proteins on the extracellular side.
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains...
The carboxy-terminal of most of the prenylated proteins, such as Ras proteins, contains...
5.6K
GPI Anchoring of Proteins in the ER Membrane
4.0K
GPI-anchoring is a post-translational, reversible protein modification that is ubiquitous in eukaryotes. Such proteins are primarily present on the exoplasmic leaflet of the plasma membrane.
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
GPI-anchor structure
A sequence of 11 enzymatic reactions results in the synthesis of the complete GPI anchor consisting of a hydrophobic and a hydrophilic portion. The hydrophobic portion comprises phosphatidylinositol, while the hydrophilic part comprises polar groups like phosphoethanolamine,...
4.0K
Cotranslational Protein Translocation
7.3K
Translocation of proteins across membranes is an ancient process that occurs even in bacteria and archaebacteria. In fact, the components of the translocation machinery are still conserved between prokaryotes and eukaryotes.
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
Sec61 channel partners for cotranslational translocation
During cotranslational translocation, the Sec61 channel partners with the signal recognition particle (SRP), the signal recognition particle receptor (SR), and the ribosomes to transport the nascent polypeptide chain...
7.3K
Structure of Porins
3.0K
Mitochondria, chloroplasts, and gram-negative bacteria have transmembrane, beta-barrel proteins called porins to mediate the free diffusion of ions and metabolites across the membrane. Mitochondrial porin precursors contain conserved amino acid sequences called beta signals at their C-terminal. Beta signals have a motif of PoXGXXHyXHy (Po-Polar, X-Any amino acid, G-Glycine, Hy-LargeHydrophobic), which are crucial for precursor recognition to initiate precursor assembly. Beta-barrel...
3.0K


