Wyniki wyszukiwania - BazTech

1

Modele eksperymentalne w badaniach zewnątrzkomórkowego transportu miedzi

Bal Wojciech

Wiadomości Chemiczne

|

2022

|

[Z] 76, 5-6

456-466

EN

The biological relevance of proteins and peptides for Cu(II) biology, including the extracellular transport of this element, is commonly estimated by studying stabilities and structures of their complexes. However, our experimental studies on the kinetics of formation of Cu(II) complexes of ATCUN/NTS and Xaa-His-R peptides, considered to be key actors in extracellular copper biology, revealed novel long-lived reaction intermediates. These intermediates, rather than the final reaction products fulfil the chemical criteria for actual biocomplexes derived from biological studies. Our research clearly demonstrated that understanding of the kinetic aspect of interactions is indispensable for realistic modeling of biological interactions of metal ions.

2

Synthetic extracellular matrix as a substrate for regenerative medicine

Stodolak-Zych Ewa, Menaszek Elżbieta, Twardy Aleksandra, Ścisłowska-Czarnecka Anna, Boguń Maciej, Kolesińska Beata

Engineering of Biomaterials

|

2019

|

Vol. 22, no. 152

10--15

EN

The work presents materials characteristics of fibrous polysaccharide substrates (calcium alginate, CA) modified with short peptides. Three types of synthesized peptides (hexapeptides) were composed of: cysteine (C) and tryptophan (W) named - (WWC)2or cysteine (C) and tyrosine (Y) named (YYC)2 or phenyloalanine (F) named 6F. The peptides size distribution (DLS method) showed that they agglomerated in an alcohol medium. These results were used to select a modification method of the fibrous substrates i.e. the peptides were deposited on the fibrous alginate substrate by the electrospraying technique. Using this method three kinds of polysaccharide- peptides systems were obtained i.e.: CA/(WWC)2, CA/(YYC)2CA/6F. As a reference material, the pure calcium alginate fibrous substrate was used. The results of modification with short peptides were evaluated via scanning electron microscopy (SEM): small aggregates were observed (40-100 nm) on the surface of fibers, and the fibers size remained the same after modification (11-12 μm). The size of aggregates depended on the kind of short peptide; the smaller (40 nm) aggregates were observed when the peptide had only aromatic chain (6F), the bigger (<100 nm) ones were observed when the peptide had heterocyclic rings in the chain (WWC and YYC). All materials were contacted with osteoblast-like cells (MG-63) to test biocompatibility (cells viability after 3 and 7 days) and the results proved showed higher viability in the polysaccharide-peptide system which increased with the time of observation. The durability of polysaccharide-peptide systems was tested using the enzymatic assay: collagenase confirmed the stability of materials. The progress of degradation rate was observed using infrared spectroscopy (FTIR-ATR) - the ratio on bands with C-O and C-OH increased after degradation under in vitro conditions.Results of the investigations on the fibrous substrates have confirmed that the system is a good model of an extracellular matrix (ECM) due to its chemical composition and microstructure which both have biomimetic characteristics. Thus, it may be used as a filling of bone defects supporting the regeneration of the damaged tissue. Additionally, it may also serve as the model research system of ECM.

3

Metoda O-acyloizopeptydowa w syntezie peptydow

Frączak O., Olma A.

Wiadomości Chemiczne

|

2014

|

[Z] 68, 7-8

733--749

EN

Proteins are macromolecules that carry out most of the biochemical functions of the cell, which strongly depend on the secondary and tertiary structure, defined by the amino acid sequence of a polypeptide chain. The importance of peptides and proteins in biology and medicine inspired chemists to develop strategies for their synthesis. The main limitation to the preparation of long peptides is their tendency to aggregation, what makes the coupling and deprotection reaction ineffective, and purification of the compounds difficult. Inter- and intramolecular interactions, hydrophobic character, the presence of multiple hydrogen bonds significantly affect the secondary structure of peptides, making further extension of the peptide chain very difficult. Undesirable aggregation process may be disrupted by reduction of hydrophobic interactions. For this purpose, various methods are used, based on the implementation of specific modifications to the peptide chain, affecting its secondary structure. These methods include, for example, incorporation of pseudoproline building blocks [5] and proximity induced peptide ligation [6, 7]. In some cases, it is convenient to extend the amino acid side chain to form isopeptides (Fig. 1) [14–16]. Depsipeptides can be created with the natural amino acids such as cysteine, serine, threonine, tyrosine, or tryptophan. The basic requirement is the presence of β-hydroxyamino component. The presence of a depsipeptide moiety in place of an amide bond significantly change the secondary structure of native peptide and prevents from aggregation, leading to higher yields of desired compounds [18]. In the solution phase peptide synthesis, this method is free from racemization [19]. Isodipeptide units can be successfully applied in SPPS for the synthesis of “difficult sequence”-containing peptides [19]. In this paper, many examples of effective use of O-acylisopeptides method in peptide synthesis are discussed.

4

Specific Interactions of Cu2+ Ions with Enantiomers of Hepatitis B Virus Surface Antigen 140-146 Region

Świątek-Kozłowska J., Brasuń J., Maćkiewicz Z., Kupryszewski G.

Polish Journal of Chemistry

|

2001

|

Vol. 75, nr 6

813-822

EN

Potentiometric and spectroscopic studies on Cu(II) interactions with 140-146 fragment of the hepatitis B virus antigen have shown that the basic binding sites of metal ion are centered at a peptide N-terminal donor system and the side chain donor atoms are not competing in the metal ion coordination.