Search results for "peptidit"
showing 10 items of 13 documents
Alternative Biosynthetic Starter Units Enhance the Structural Diversity of Cyanobacterial Lipopeptides
2019
Puwainaphycins (PUWs) and minutissamides (MINs) are structurally analogous cyclic lipopeptides possessing cytotoxic activity. Both types of compound exhibit high structural variability, particularly in the fatty acid (FA) moiety. Although a biosynthetic gene cluster responsible for synthesis of several PUW variants has been proposed in a cyanobacterial strain, the genetic background for MINs remains unexplored. Herein, we report PUW/MIN biosynthetic gene clusters and structural variants from six cyanobacterial strains. Comparison of biosynthetic gene clusters indicates a common origin of the PUW/MIN hybrid nonribosomal peptide synthetase and polyketide synthase. Surprisingly, the biosynthet…
Characterization of the interaction of the antifungal and cytotoxic cyclic glycolipopeptide hassallidin with sterol-containing lipid membranes.
2019
Hassallidins are cyclic glycolipopeptides produced by cyanobacteria and other prokaryotes. The hassallidin structure consists of a peptide ring of eight amino acids where a fatty acid chain, additional amino acids, and sugar moieties are attached. Hassallidins show antifungal activity against several opportunistic human pathogenic fungi, but does not harbor antibacterial effects. However, they have not been studied on mammalian cells, and the mechanism of action is unknown. We purified hassallidin D from cultured cyanobacterium Anabaena sp. UHCC 0258 and characterized its effect on mammalian and fungal cells. Ultrastructural analysis showed that hassallidin D disrupts cell membranes, causin…
The structure and biosynthesis of heinamides A1-A3 and B1-B5, antifungal members of the laxaphycin lipopeptide family.
2021
Laxaphycins are a family of cyclic lipopeptides with synergistic antifungal and antiproliferative activities. They are produced by multiple cyanobacterial genera and comprise two sets of structurally unrelated 11- and 12-residue macrocyclic lipopeptides. Here, we report the discovery of new antifungal laxaphycins from Nostoc sp. UHCC 0702, which we name heinamides, through antimicrobial bioactivity screening. We characterized the chemical structures of eight heinamide structural variants A1-A3 and B1-B5. These variants contain the rare non-proteinogenic amino acids 3-hydroxy-4-methylproline, 4-hydroxyproline, 3-hydroxy-d-leucine, dehydrobutyrine, 5-hydroxyl beta-amino octanoic acid, and O-c…
Scalable Constant pH Molecular Dynamics in GROMACS
2022
Molecular dynamics (MD) computer simulations are used routinely to compute atomistic trajectories of complex systems. Systems are simulated in various ensembles, depending on the experimental conditions one aims to mimic. While constant energy, temperature, volume, and pressure are rather straightforward to model, pH, which is an equally important parameter in experiments, is more difficult to account for in simulations. Although a constant pH algorithm based on the λ-dynamics approach by Brooks and co-workers [Kong, X.; Brooks III, C. L. J. Chem. Phys.1996, 105, 2414–2423] was implemented in a fork of the GROMACS molecular dynamics program, uptake has been rather limited, presumably due to…
Cyanobacteria and their metabolites in mono- and polidominant shallow eutrophic temperate lakes
2022
Monodominant (one species dominates) or polidominant (multiple species dominate) cyanobacterial blooms are pronounced in productive freshwater ecosystems and pose a potential threat to the biota due to the synthesis of toxins. Seasonal changes in cyanobacteria species and cyanometabolites composition were studied in two shallow temperate eutrophic lakes. Data on cyanobacteria biomass and diversity of dominant species in the lakes were combined with chemical and molecular analyses of fifteen potentially toxin-producing cyanobacteria species (248 isolates from the lakes). Anatoxin-a, saxitoxin, microcystins and other non-ribosomal peptides formed the diverse profiles in monodominant (Planktot…
Flexible Structure of Peptide-Bound Filamin A Mechanosensor Domain Pair 20-21.
2015
Filamins (FLNs) are large, multidomain actin cross-linking proteins with diverse functions. Besides regulating the actin cytoskeleton, they serve as important links between the extracellular matrix and the cytoskeleton by binding cell surface receptors, functioning as scaffolds for signaling proteins, and binding several other cytoskeletal proteins that regulate cell adhesion dynamics. Structurally, FLNs are formed of an amino terminal actin-binding domain followed by 24 immunoglobulin-like domains (IgFLNs). Recent studies have demonstrated that myosin-mediated contractile forces can reveal hidden protein binding sites in the domain pairs IgFLNa18-19 and 20-21, enabling FLNs to transduce me…
Filamiini A:n ja taliinin sitoutuminen β7- ja β1A-integriinien sytoplasmisiin domeeneihin
2006
Sappihappojen aminohappo- ja oligopeptidikonjugaatit
2012
Kirjallisen osion tarkoituksena on esitellä sappihappojen aminohappo- ja oligopeptidikonjugaatteja ja niiden synteettistä valmistusta sekä perehtyä niiden erilaisiin käyttömahdollisuuksiin. Sappihappojen aminohappo- ja oligopeptidikonjugaateista valmistetut makrosykliset rakenteet voivat toimia mm. rakenneosina lääkekehityksessä, materiaalikemiassa ja supramolekyylikemiassa. Sappihappo- ja aminohappokonjugaatteja on tutkittu myös ionikuljettimina, reseptoreina ja gelaattoreina.Tutkielman kokeellisen osion tarkoituksena oli valmistaa sappihappojen aminoetyy-liamidien ja L-proliinin konjugaatteja sekä tutkia niiden geelinmuodostusominaisuuksia eri liuottimissa.
Probing the Gelation Synergies and Anti-Escherichia coli Activity of Fmoc-Phenylalanine/Graphene Oxide Hybrid Hydrogel
2023
The N-fluorenyl-9-methyloxycarbonyl (Fmoc)-protected amino acids have shown high antimicrobial application potential, among which the phenylalanine derivative (Fmoc-F) is the most well-known representative. However, the activity spectrum of Fmoc-F is restricted to Gram-positive bacteria only. The demand for efficient antimicrobial materials expanded research into graphene and its derivatives, although the reported results are somewhat controversial. Herein, we combined graphene oxide (GO) flakes with Fmoc-F amino acid to form Fmoc-F/GO hybrid hydrogel for the first time. We studied the synergistic effect of each component on gelation and assessed the material’s bactericidal activity on Gram…
Oligopeptidipäällysteiset kultananopartikkelit lääketieteellisissä sovelluksissa
2016
Pro Gradu -tutkielmassa käsitellään oligopeptidipäällysteisten kultananopartikkeleiden sovelluksia lääketieteessä. Tutkielmassa käydään läpi kultananopartikkeleiden yleisiä ominaisuuksia sekä niiden soveltuvuutta biologisiin ja lääketieteellisiin sovelluksiin. Lisäksi esitellään yleisimmät kultananopartikkeleiden päällystyksessä käytettävät oligopeptidit ja kuvataan erityyppisille oligopeptidipäällysteisille kultananopartikkeleille kehiteltyjä lääketieteellisiä sovelluksia, joihin lukeutuvat muun muassa syöpähoito, biologinen kuvantaminen, kolorimetriset biomolekyylianalyysit ja lääkeaineiden kohdennettu kuljetus. Kokeellisessa osassa pyrittiin valmistamaan tiolifunktionalisoitu oligopeptid…