stoichiometry optimization
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Targeted cancer immunotherapy is a promising tool for restoring immune surveillance and eradicating cancer cells. Hydrophilic polymers modified with coiled coil peptide tags can be used as universal carriers designed for cell-specific delivery of such biologically active proteins. Here, we describe the preparation of pHPMA-based copolymer conjugated with immunologically active protein B7-H6 via complementary coiled coil VAALEKE (peptide E) and VAALKEK (peptide K) sequences. Receptor B7-H6 was described as a binding partner of NKp30, and its expression has been proven for various tumor cell lines. The binding of B7-H6 to NKp30 activates NK cells and results in Fas ligand or granzyme-mediated apoptosis of target tumor cells. In this work, we optimized the expression of coiled coil tagged B7-H6, its ability to bind activating receptor NKp30 has been confirmed by isothermal titration calorimetry, and the binding stoichiometry of prepared chimeric biopolymer has been characterized by analytical ultracentrifugation. Furthermore, this coiled coil B7-H6-loaded polymer conjugate activates NK cells in vitro and, in combination with coiled coil scFv, enables their targeting towards a model tumor cell line. Prepared chimeric biopolymer represents a promising precursor for targeted cancer immunotherapy by activating the cytotoxic activity of natural killer cells.
- Publikační typ
- časopisecké články MeSH
Procedures for the extraction-spectrophotometric determination of tris(2-chloroethyl)amine, an alkylating agent known as a drug as well as a chemical warfare agent (nitrogen mustard HN-3), with 7 acid-base indicators of a triphenylmethane lactone type, phthaleins, were developed. Representatives of phthaleins without an oxygen bridge (thymolphthalein, o-cresolphthalein, naphtholphthalein) and with an oxygen bridge (fluorescein, 2',7'-dichlorofluorescein, eosin B and eosin Y) were used. The methods were based on the formation of ion pair complexes. Chloroform was used as a non-polar solvent for an extraction. The conditions to determine were optimized for the optimal pH of the buffer and the concentration of a phthalein as a reagent. The dependence on the reaction time in a water phase and the stoichiometry of extraction products were studied. The detection limits and the limits of the determination of separate procedures and conditional extraction constants were determined. Comparison with the spectrophotometric method of the group determination of alkyl halides and acyl halides using alkaline ethanol-water solution of thymolphthalein, the so-called T-135 agent, was conducted. While studying the selectivity, the possible interference of bis(2-chloroethyl)sulphide and 3 nitrogen mustards in the proposed procedures were verified. Copyright © 2016 John Wiley & Sons, Ltd.
- MeSH
- alkylační látky analýza izolace a purifikace MeSH
- chemické bojové látky analýza izolace a purifikace MeSH
- fenolftaleiny chemie MeSH
- koncentrace vodíkových iontů MeSH
- limita detekce MeSH
- pufry MeSH
- sloučeniny dusíkatého yperitu analýza izolace a purifikace MeSH
- spektrofotometrie metody MeSH
- voda analýza MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
Most heterotrophic organisms feed on substrates that are poor in nutrients compared to their demand, leading to elemental imbalances that may constrain their growth and function. Flexible carbon (C)-use efficiency (CUE, C used for growth over C taken up) can represent a strategy to reduce elemental imbalances. Here, we argue that metabolic regulation has evolved to maximise the organism growth rate along gradients of nutrient availability and translated this assumption into an optimality model that links CUE to substrate and organism stoichiometry. The optimal CUE is predicted to decrease with increasing substrate C-to-nutrient ratio, and increase with nutrient amendment. These predictions are generally confirmed by empirical evidence from a new database of c. 2200 CUE estimates, lending support to the hypothesis that CUE is optimised across levels of organisation (microorganisms and animals), in aquatic and terrestrial systems, and when considering nitrogen or phosphorus as limiting nutrients.
Solvatochromic probes are suitable tools for quantitative characterization of protein-membrane interactions. Based on diverse fluorophores these probes have different fluorescent properties and therefore demonstrate different responses when applied for sensing the interactions of biomolecules. Surprisingly, to the best of our knowledge, no systematic comparison of the sensitivities of solvatochromic dyes for monitoring protein-membrane interactions was described. Hence, a rational choice of an optimal environmentally sensitive probe for such experiments is usually not a straightforward task. In this work we developed a series of thiol-reactive fluorescent probes based on the fluorophores with high sensitivity to their environment and compared them with two widely used DNS and DMN probes. We investigated the responses of these probes to the interaction of probe-labeled presynaptic protein α-synuclein with lipid membranes. We observed that newly synthesized probes based on fluorene and chromone dyes, which combine the strongest brightness and significant changes of fluorescence intensity, demonstrated the highest sensitivity to interaction of α-synuclein with lipid membranes. They are especially beneficial for sensing in scattering media such as solutions of lipid vesicles. We show that the described probes permit quantitative measurements of α-synuclein binding to lipid membranes at low nanomolar concentrations. We developed a detailed protocol for measuring Kd and binding stoichiometry for interaction of soluble peripheral proteins with membranes based on the response of the environmentally sensitive fluorescent probes. We applied this protocol for quantification of the affinity of α-synuclein to anionic membranes and found that it is substantially higher than it was earlier reported.
Multienzyme processes represent an important area of biocatalysis. Their efficiency can be enhanced by optimization of the stoichiometry of the biocatalysts. Here we present a workflow for maximizing the efficiency of a three-enzyme system catalyzing a five-step chemical conversion. Kinetic models of pathways with wild-type or engineered enzymes were built, and the enzyme stoichiometry of each pathway was optimized. Mathematical modeling and one-pot multienzyme experiments provided detailed insights into pathway dynamics, enabled the selection of a suitable engineered enzyme, and afforded high efficiency while minimizing biocatalyst loadings. Optimizing the stoichiometry in a pathway with an engineered enzyme reduced the total biocatalyst load by an impressive 56 %. Our new workflow represents a broadly applicable strategy for optimizing multienzyme processes.
RATIONALE: Rare earth-doped sulphide glasses in the Ga-Ge-Sb-S system present radiative emissions from the visible to the middle infrared range (mid-IR) range, which are of interest for a variety of applications including (bio)-chemical optical sensing, light detection, and military counter-measures. The aim of this work was to reveal structural motifs present during the fabrication of thin films by plasma deposition techniques as such knowledge is important for the optimization of thin film growth. METHODS: The formation of clusters in plasma plume from different concentrations of erbium-doped Ga5Ge20Sb10S65 glasses (0.05, 0.1, and 0.5 wt. % of erbium) using laser (337 nm) desorption ionization (LDI) was studied by time-of-flight mass spectrometry (TOF MS) in both positive and negative ion mode. The stoichiometry of the Ga(m)Ge(n)Sb(o)S(p)(+/-) clusters was determined via isotopic envelope analysis and computer modelling. RESULTS: Several Ga(m)Ge(n)Sb(o)S(p)(+/-) singly charged clusters were found but, surprisingly, only four species (Sb3S4(+/-), GaSb2S(p)(+/-) (p = 4, 5), Ga3Sb2S7(+/-) ) were common to both ion modes. For the first time, species containing rare earths (GaSb2SEr(+) and GaS6 Er2(+)) were identified in the plasma formed from rare earth-doped chalcogenide glasses, directly confirming the importance of gallium presence for rare earth bonding within the glassy matrix. CONCLUSIONS: The local structure of Ga-Ge-Sb-S glasses is at least partly different from the structure of species identified in plasma by mass spectrometry, as deduced from Raman scattering spectroscopy analysis; these glasses are mainly formed by [GeS4/2]/[GaS4/2] tetrahedra and [SbS3/2] pyramids. Extended X-ray absorption fine structure measurements show that Er(3+) ions in Ga-Ge-Sb-S glasses are surrounded by 7 sulphur atoms.
... Multiparameter Optimization 117 -- 3.10. ... ... APPLICATIONS OF HPCE -- CHAPTER 19 PEPTIDE ANALYSIS BY CAPILLARY ELECTROPHORESIS: METHODS DEVELOPMENT AND OPTIMIZATION ... ... Determination of Stoichiometry of Binding 964 -- 29.9. ...
Chemical analysis ; 146
1047 s.
- Klíčová slova
- elektroforéza kapilární,
- Konspekt
- Biochemie. Molekulární biologie. Biofyzika
- NLK Obory
- fyzika, biofyzika
- biomedicínské inženýrství
