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Biochemical and Biophysical Research... Oct 2014When mRNAs lack stop codons, errors in gene expression and coding of aberrant proteins that are harmful in cells can result. In Saccharomyces cerevisiae, a 180-kDa...
When mRNAs lack stop codons, errors in gene expression and coding of aberrant proteins that are harmful in cells can result. In Saccharomyces cerevisiae, a 180-kDa E3-ubiquitin ligase, Ltn1 has been known to associate with ribosomes and marks translationally-arrested aberrant nascent polypeptides for proteasomal degradation. Here, we demonstrate the Ltn1 E3-ubiquitin ligase directly binds to the nonstop proteins and efficiently ubiquitylates them. The middle domain of Ltn1 is responsible for recognizing the polylysine residues of the nonstop protein with an affinity of 2-3μM. This biochemical characterization of Ltn1 expands our knowledge regarding the fundamental process that removes aberrant nascent polypeptides in eukaryotes.
Topics: Binding Sites; Polylysine; Saccharomyces cerevisiae Proteins; Ubiquitin-Protein Ligases; Ubiquitination
PubMed: 25305489
DOI: 10.1016/j.bbrc.2014.10.003 -
Comptes Rendus Des Seances de La... 1996A process for the selective transfer of genes using glycosylated polylysine was established. Glycosylated polylysines and plasmid DNA form complexes which are taken up... (Review)
Review
A process for the selective transfer of genes using glycosylated polylysine was established. Glycosylated polylysines and plasmid DNA form complexes which are taken up by cells expressing surface lectins recognizing the sugar moieties of glycosylated polylysines. Modifications made to this process allow for efficient and specific transfer in in vitro animal cell models.
Topics: Animals; In Vitro Techniques; Polylysine; Signal Recognition Particle; Transfection
PubMed: 8881267
DOI: No ID Found -
The Journal of Pharmacy and Pharmacology Apr 1980Polylysines of 7-371 lysine residues inhibited pepsin over the pH range 3.6-5.0 in a system using azocoll as substrate. Tetralysine was inactive. An almost 1:1 molar...
Polylysines of 7-371 lysine residues inhibited pepsin over the pH range 3.6-5.0 in a system using azocoll as substrate. Tetralysine was inactive. An almost 1:1 molar ratio with pepsin gave maximum inhibition for a polylysine containing 59 lysine residues but increase in polylysine molecular size beyond this size was not accompanied by increase in activity on a weight basis although the polylysine:pepsin molar ratio for maximum inhibition decreased and inhibition mechanism varied. Polylysines of 59 and 158 lysine residues which were intermediate in the series were non-competitive inhibitors, whilst polylysines of greater and smaller molecular size were competitive inhibitors, although only the smallest inhibitory polylysine, containing 7 lysine residues, was a pure competitive inhibitor. Polylysine inhibition of pepsin was found to be strongest at pH 5.0 and the pH dependence appeared to be associated with the relative concentrations of the enzyme and inhibitors in ionized form. For each polylysine it was possible to detect a polylysine:pepsin concentration ratio for which inhibition was pH-independent over the range 3.6-5.0.
Topics: Binding, Competitive; Cations; Kinetics; Molecular Weight; Pepsin A; Peptides; Polylysine
PubMed: 6103053
DOI: 10.1111/j.2042-7158.1980.tb12907.x -
Applied Microbiology and Biotechnology Jul 2003epsilon-Poly-L-lysine (epsilon-PL) is a homo-poly-amino acid characterized by the peptide bond between the carboxyl and epsilon-amino groups of L-lysine. epsilon-PL... (Review)
Review
epsilon-Poly-L-lysine (epsilon-PL) is a homo-poly-amino acid characterized by the peptide bond between the carboxyl and epsilon-amino groups of L-lysine. epsilon-PL shows a wide range of antimicrobial activity and is stable at high temperatures and under both acidic and alkaline conditions. The mechanism of the inhibitory effect of epsilon-PL on microbial growth is the electrostatic adsorption to the cell surface of microorganisms on the basis of its poly-cationic property. Due to this antimicrobial activity, epsilon-PL is now industrially produced in Japan as a food additive by a fermentation process using Streptomyces albulus. In spite of the practical application of epsilon-PL, the biosynthetic mechanisms of epsilon-PL have not been clarified at all. epsilon-PL producers commonly possess membrane-bound epsilon-PL-degrading aminopeptidase, which might play a role in self-protection.
Topics: Bacteria; Biodegradation, Environmental; Biotechnology; Food Additives; Models, Molecular; Polylysine; Streptomyces
PubMed: 12728342
DOI: 10.1007/s00253-003-1312-9 -
Pharmacology & Therapeutics Feb 2015Although cancer vaccination has yielded promising results in patients, the objective response rates are low. The right choice of adjuvant might improve the efficacy.... (Review)
Review
Although cancer vaccination has yielded promising results in patients, the objective response rates are low. The right choice of adjuvant might improve the efficacy. Here, we review the biological rationale, as well as the preclinical and clinical results of polyinosinic:polycytidylic acid and its derivative poly-ICLC as cancer vaccine adjuvants. These synthetic immunological danger signals enhanced vaccine-induced anti-tumor immune responses and contributed to tumor elimination in animal tumor models and patients. Supported by these results, poly-ICLC-containing cancer vaccines are currently extensively studied in the ongoing trials, making it highly plausible that poly-ICLC will be part of the future approved cancer immunotherapies.
Topics: Adjuvants, Immunologic; Animals; Cancer Vaccines; Carboxymethylcellulose Sodium; Humans; Poly I-C; Polylysine
PubMed: 25281915
DOI: 10.1016/j.pharmthera.2014.09.010 -
Archives of Biochemistry and Biophysics Apr 1983Polycation binding to the negatively charged surface of chloroplast thylakoid membranes is known to cause an inhibition of photosystem I activity. It also interferes...
Polycation binding to the negatively charged surface of chloroplast thylakoid membranes is known to cause an inhibition of photosystem I activity. It also interferes with the cation-dependent rearrangement of chlorophyll proteins in the thylakoid membrane. It was shown that added anions prevented or reversed the inhibition of photosystem I by polylysine without decreasing its binding to the membranes. Anions also caused a change in the interaction of the chlorophyll proteins in polylysine-treated thylakoids as indicated by an increase in the relative fluorescence intensity from photosystem II. In both cases, the relative effectiveness of the anions tested depended on their valence; for example, the tetravalent species Fe(CN)4-(6) was effective at concentration at least 2 orders of magnitude lower than the divalent species SO2-(4). These results suggest that anions act by screening the positive charge of the polylysine-coated membrane surface. Measurements of the response of the anionic fluorescent probe 1-anilinonapthalene-8-sulfonate to an addition of anions to polylysine-treated thylakoids supported this contention. It was concluded that the action of polylysine on photosystem I and on the chlorophyll proteins is mediated by changes of the electrical properties of the thylakoid membrane and may not involve a direct binding of the polycation to the affected membrane proteins.
Topics: Anions; Binding Sites; Chloroplasts; Electrochemistry; Electron Transport; Fabaceae; Membrane Proteins; Peptides; Photochemistry; Plant Proteins; Plants, Medicinal; Plastocyanin; Polylysine; Surface Properties
PubMed: 6838230
DOI: 10.1016/0003-9861(83)90503-9 -
Journal of Controlled Release :... Mar 2000A series of lipidic peptide dendrimers based on lysine with 16 surface alkyl (C(12)) chains has been synthesised in our laboratories. One of the series, a fourth...
A series of lipidic peptide dendrimers based on lysine with 16 surface alkyl (C(12)) chains has been synthesised in our laboratories. One of the series, a fourth generation dendrimer with a diameter of 2.5 nm was chosen to study its absorption after oral administration to female Sprague-Dawley rats (180 g, 9 weeks old). It was synthesised as the tritiated derivative (all acetyl portions) and had a molecular weight of 6300 and log P (octanol/water) of 1.24. First a single oral dose 14 mg/kg was administered by gavage. Maximum levels of dendrimer observed were 15% in the small intestine, 5% in the large intestine and 3% in the blood at 6 h after administration, while 1.5% reached the liver, 0.1% the spleen and 0. 5% the kidneys. In a parallel study with a higher dose of 28 mg/kg, approximately 1% was absorbed via Peyer's patches of the small intestine at 3 h. The maximum uptake by small intestine enterocytes was 4% of the dose after 3 h. After 12 h, 0.3 and 4% dendrimer was measured respectively in Peyer's patches and enterocytes of the large intestine. When calculated on the basis of target tissue weight, the total percentage of the dose absorbed through Peyer's patches was greater than through normal enterocytes in the small intestine after 3 and 24 h, but the opposite was true in the large intestine. These levels of uptake and translocation are lower than those exhibited by polystyrene particles in the range from 50 to 3000 nm. This might suggest that there is an optimum size for nanoparticulate uptake by the gut.
Topics: Animals; Enterocytes; Female; Intestinal Absorption; Lipids; Microspheres; Molecular Weight; Particle Size; Peyer's Patches; Polylysine; Polystyrenes; Rats; Rats, Sprague-Dawley; Surface Properties; Tissue Distribution
PubMed: 10699285
DOI: 10.1016/s0168-3659(99)00237-0 -
Biotechnology Letters Mar 2008Poly(epsilon-L-lysine) (epsilon-PL) is a naturally occurring poly(amino acid) characterized by a unique structure linking epsilon-amino and carboxyl groups of L-lysine.... (Review)
Review
Poly(epsilon-L-lysine) (epsilon-PL) is a naturally occurring poly(amino acid) characterized by a unique structure linking epsilon-amino and carboxyl groups of L-lysine. Due to its various functions and its biodegradability and non-toxicity, the epsilon-PL polymer has attracted increasing attention in recent years. epsilon-PL is frequently found in various strains of Streptomyces sp. This review gives an up-to-date overview regarding the biosynthesis of epsilon-PL focussing mainly on results obtained from ten newly isolated producer strains, using the two-stage culture method of cell growth and epsilon-PL production cultures. The production of nearly monodispersed epsilon-PL is covered together with the development of epsilon-PL specific hydrolases and the release of synthesized epsilon-PL into the culture broth. From these results, coupled with the termination of polymerization through nucleophilic chain transfer, the biosynthetic mechanism of the polymer is discussed.
Topics: Culture Media; Fermentation; Hydrolases; Polylysine; Streptomyces
PubMed: 17985083
DOI: 10.1007/s10529-007-9563-7 -
Journal of Colloid and Interface Science Jan 2015Understanding the factors that governs spontaneous molecular transfer from solution to solid surface is fundamental to control noncovalent surface functionalization...
Understanding the factors that governs spontaneous molecular transfer from solution to solid surface is fundamental to control noncovalent surface functionalization strategies, both in term of robustness and reproducibility. The comprehension of the nature of interaction involved in the mechanism of spontaneous adsorption will allow for a fine modulation of the deposition process. Herein, we provide experimental evidences to demonstrate that poly-lysine secondary structure represents a crucial factor profoundly influencing the outcome of its spontaneous deposition on quartz surfaces. In particular, random coil to α-helix transition is required to drive an effective transfer of the poly-l-lysine at the liquid-solid interface. β-sheet deposition requires longer times to be accomplished, while random-coil deposition is highly unfavored. Accordingly, polylysine deposition on quartz and silicon is effective when α-helix is formed in solution (pH>10). This surface noncovalent functionalization represents a simple strategy to fabricate hybrid organic-inorganic or biocompatible materials. In fact, the proposed methodology is proven robust and repeatable and compatible for combination with solution or vapor phases (i.e. MOCVD) nanomaterial deposition approaches.
Topics: Circular Dichroism; Microscopy, Electron, Scanning; Polylysine; Protein Structure, Secondary; Spectrophotometry, Ultraviolet; Surface Properties
PubMed: 25441360
DOI: 10.1016/j.jcis.2014.09.049 -
The Journal of General Virology Jun 1988We earlier reported that neomycin blocked reversibly the binding of herpes simplex virus type 1 (HSV-1) to the receptor of BHK cells, while the binding of HSV-2 to the...
We earlier reported that neomycin blocked reversibly the binding of herpes simplex virus type 1 (HSV-1) to the receptor of BHK cells, while the binding of HSV-2 to the receptor was unaffected. We could not determine whether the effect was on the virus particle, the receptor, or both. We have now tested several other cationic substances, and report that polylysine (and polyarginine) block the binding of HSV-1 to the receptor by interfering with the cellular receptor function; higher molecular weight polylysines were more potent than those of lower molecular weight. Polylysine and neomycin showed additive effects. In vitro, polylysine showed the same strong binding to the plasma membrane phosphoinositides as did neomycin. Together these data suggest that the drugs may have a common target in the cell membrane. The HSV-1 and HSV-2 virus particles were unaffected by the drugs, as was the cellular HSV-2 receptor.
Topics: Animals; Cell Line; Cell Membrane; Membrane Lipids; Neomycin; Peptides; Phosphatidylinositols; Phospholipids; Polylysine; Receptors, Virus; Simplexvirus; Time Factors
PubMed: 2838567
DOI: 10.1099/0022-1317-69-6-1137