Newly synthesized membrane and secretory proteins in cells undergo folding in the endoplasmic reticulum with the introduction of disulfide bonds and acquire the correct three-dimensional structure. Disulfide bonds are...Newly synthesized membrane and secretory proteins in cells undergo folding in the endoplasmic reticulum with the introduction of disulfide bonds and acquire the correct three-dimensional structure. Disulfide bonds are especially important for protein folding. It has been thought that formation of protein disulfide bonds in eukaryotes is mainly carried out by an enzyme called protein disulfide isomerase. Proteins, bearing the C-terminus of amino acids sequences with His-Asp-Glu-Leu (HDEL) sequence in yeast, in the endoplasmic reticulum (ER), which is a eukaryotic cellular organelle involved in protein synthesis, processing, and transport, have been considered to recycle between ER and Golgi apparatus. The proposal for this recycling model derives from the study of an HDEL-tagged fusion protein. Here, the localization and oligosaccharide modification of protein disulfide isomerase were investigated in yeast, and showed the first direct evidence that this intrinsic ER protein transports from ER to Golgi. Results suggest that this native protein is also accessible to post-ER enzymes, and yet accumulates in the ER.展开更多
We apply the localized surface plasrnon resonance （LSPR） of gold nanoparticles （GNPs） covalently coupled with cytochrorne c （cyt c） to create a nanobiosensor for detecting hydrogen sulfide （H2S） in the range o...We apply the localized surface plasrnon resonance （LSPR） of gold nanoparticles （GNPs） covalently coupled with cytochrorne c （cyt c） to create a nanobiosensor for detecting hydrogen sulfide （H2S） in the range of 15 lOOppb. Monolayer formation of GNPs on glass surface functionalized with 3-aminopropyltrirnethoxysilane （APTMS） is performed for fabricating a chip-based format of the optical transducer. By chemical introduction of short-chain thiol derivatives on cyt c protein shell via its lysine residues, a very fast self-assembled rnonolayer （SAM） of cyt c is formed on the GNPs. Significant shifts in the LSPR peak （△λLSPR） are observed by reacting H2S with cyt c. Results show a linear relationship between △λLSPR and H2S concentration. Furthermore, shifts in the LSPR peak are reversible and the peak positions return to their pre-exposure values once the H2S is removed. The experirnental results strongly indicate that the protein based LSPR chip can be successfully used as a simple, fast, sensitive and quantitative sensor for H2S detection.展开更多
In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among th...In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among them, Crumbs （Crb） is the only trans- membrane polarity protein characterized to date （Tepass et al.,展开更多
文摘Newly synthesized membrane and secretory proteins in cells undergo folding in the endoplasmic reticulum with the introduction of disulfide bonds and acquire the correct three-dimensional structure. Disulfide bonds are especially important for protein folding. It has been thought that formation of protein disulfide bonds in eukaryotes is mainly carried out by an enzyme called protein disulfide isomerase. Proteins, bearing the C-terminus of amino acids sequences with His-Asp-Glu-Leu (HDEL) sequence in yeast, in the endoplasmic reticulum (ER), which is a eukaryotic cellular organelle involved in protein synthesis, processing, and transport, have been considered to recycle between ER and Golgi apparatus. The proposal for this recycling model derives from the study of an HDEL-tagged fusion protein. Here, the localization and oligosaccharide modification of protein disulfide isomerase were investigated in yeast, and showed the first direct evidence that this intrinsic ER protein transports from ER to Golgi. Results suggest that this native protein is also accessible to post-ER enzymes, and yet accumulates in the ER.
文摘We apply the localized surface plasrnon resonance （LSPR） of gold nanoparticles （GNPs） covalently coupled with cytochrorne c （cyt c） to create a nanobiosensor for detecting hydrogen sulfide （H2S） in the range of 15 lOOppb. Monolayer formation of GNPs on glass surface functionalized with 3-aminopropyltrirnethoxysilane （APTMS） is performed for fabricating a chip-based format of the optical transducer. By chemical introduction of short-chain thiol derivatives on cyt c protein shell via its lysine residues, a very fast self-assembled rnonolayer （SAM） of cyt c is formed on the GNPs. Significant shifts in the LSPR peak （△λLSPR） are observed by reacting H2S with cyt c. Results show a linear relationship between △λLSPR and H2S concentration. Furthermore, shifts in the LSPR peak are reversible and the peak positions return to their pre-exposure values once the H2S is removed. The experirnental results strongly indicate that the protein based LSPR chip can be successfully used as a simple, fast, sensitive and quantitative sensor for H2S detection.
基金supported by the grants from the National Institutes of Health of USA(NCRR R21RR024869, NIGMS RO1GM086423 and RO1GM121534 to Y.H.)the Start-up Foundation from Nanjing Medical University (2012RC04 to J.H.)University of Pittsburgh Medical School Center for Biologic Imaging was supported by the grant 1S100D019973-01 from NIH, USA
文摘In the past two decades, extensive studies have focused on a group of so-called polarity proteins that play conserved and essential functions in establishing and maintaining cell polarity in epithelial cells. Among them, Crumbs （Crb） is the only trans- membrane polarity protein characterized to date （Tepass et al.,
