scholarly journals THE PROCESS OF SELF-ORGANIZATION IN LOW-CONCENTRATED AQUEOUS SYSTEMS BASED ON N-ACETYL-L-CYSTEINE, L-CYSTEINE AND SILVER ACETATE

2020 ◽  
pp. 70-82
Author(s):  
Дмитрий Вадимович Аверкин ◽  
Дмитрий Викторович Вишневецкий ◽  
Владимир Романович Петров ◽  
Светлана Дмитриевна Хижняк ◽  
Павел Михайлович Пахомов
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Uv Spectroscopy ◽  
Self Organization ◽  
Amino Acid Residues ◽  
Silver Acetate ◽  
The Core ◽  
Organization Process ◽  
Silver Cations ◽  
Comprehensive Study

Проведено комплексное исследование процесса самоорганизации при сливании низкоконцентрированных водных растворов N-ацетил-L-цистеина и ацетата серебра. Все стадии самоорганизации изучены c помощью измерения величины рН, методов вискозиметрии, УФ спектроскопии и динамического светорассеяния (ДСР). Установлено, что началом самосборки является замена водорода в меркаптогруппе аминокислоты на катион серебра с образованием молекулы меркаптида серебра (МС). Далее происходит образование цепочек вида (-Ag-S(NCys)-Ag-S(NCys)-), при этом происходит протонирование аминокислотных остатков N-ацетил-L-цистеина. Предложен механизм самоорганизации в водном растворе N-ацетил-L-цистеина и ацетата серебра (N-ацетилцистеин-серебряный раствор - НАЦ), заключающийся в образовании агрегатов типа «ядро-оболочка». «Ядро» агрегатов состоит из цепочек вида (-Ag-S(NCys)-Ag-S(NCys)-), «оболочка» агрегатов состоит из протонированных аминокислотных остатков. Связывание таких агрегатов происходит посредством образования связей с ацетат-анионами. A comprehensive study of the self-organization process during the draining of low-concentration aqueous solutions of N-acetyl-L-cysteine and silver acetate was carried out. All stages of self-organization have been studied using pH measurements, viscometry, UV spectroscopy, and dynamic light scattering (DLS). It was found that the first stage of self-assembly is the replacement of hydrogen in the mercapto group of an amino acid with a silver cation with the formation of a silver mercaptide (MS) molecule. Further, the formation of chains of the form (-Ag-S(NCys)-Ag-S(NCys)-) occurs, while excess electron density is retained in amino acid residues, leading to the interaction of chains with both silver cations and undissociated silver acetate molecules , with the formation of clusters. The mechanism of self-organization of the system as the formation of the aggregates of the «core-shell» type is proposed. The «core» consists of chains of the form (-Ag-S(NCys)-Ag-S(NCys)-), the «shell» consists of protonated N-acetyl-L-cysteine resides. Further bonding of aggregates into clusters occurs through free acetic acid anions.

scholarly journals INFLUENCE OF LIGHTING ON THE SELF-ORGANIZATION PROCESS IN CYSTEINE-SILVER SOLUTION

2021 ◽  
pp. 60-68
Author(s):  
Анна Нориковна Адамян ◽  
Александра Ивановна Иванова ◽  
Елена Михайловна Семенова ◽  
Максим Дмитриевич Малышев ◽  
Светлана Дмитриевна Хижняк ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Plasmon Resonance ◽  
Self Assembly ◽  
The Self ◽  
Self Organization ◽  
Assembly Process ◽  
Silver Acetate ◽  
Silver Solution ◽  
Organization Process

Комплексно исследовано влияние дневного освещения на процесс самоорганизации в цистеин-серебряном растворе (ЦСР) и гидрогелях на его основе. Установлено, что ЦСР на основе L-цистеина и ацетата серебра под действием освещения окрашивается сначала в желтый, а затем в коричневый цвет, что является следствием плазмонного резонанса на образующихся наночастицах серебра (НЧС) в ЦСР и гидрогелях. Предложена модель формирования НЧ в гидрогеле. The effect of daylight on the self-assembly process in cysteine-silver solution (CSS) and hydrogels based on it has been comprehensively studied. It was found that CSS based on L-cysteine and silver acetate under the action of illumination first turns yellow and then brown, which is a consequence of plasmon resonance on the resulting silver nanoparticles in CSS and hydrogels. A model for the formation of silver nanoparticles in a hydrogel is proposed.

Engineering two mutants of cDNA-encoding G2 subunit of soybean glycinin capable of self-assembly in vitro and rich in methionine

Biologia ◽  
2007 ◽  
Vol 62 (4) ◽  
Author(s):  
Reda Sammour
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Seed Quality ◽  
Amino Acid Residues ◽  
Methionine Residues

AbstractThe main goal of this work was to make the cDNA-encoding subunit G2 of soybean glycinin, capable of self-assembly in vitro and rich in methionine residues. Two mutants (pSP65/G4SacG2 and pSP65/G4SacG2HG4) were therefore constructed. The constructed mutants were successfully assembled in vitro into oligomers similar to those occurred in the seed. The successful self-assembly was due to the introduction of Sac fragment of Gy4 (the codons of the first 21 amino acid residues), which reported to be the key element in self-assembly into trimers. The mutant pSP65/G4SacG2HG4 included the acidic chain of Gy4 (HG4), which was previously molecularly modified to have three methionine residues. This mutant will be useful in the efforts to improve the seed quality.

scholarly journals Identification of critical amino acid residues in the regulatory N-terminal domain of PMEL

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Susan M. Mitchell ◽  
Morven Graham ◽  
Xinran Liu ◽  
Ralf M. Leonhardt
Keyword(s):  
Amino Acid ◽  
Pigment Cell ◽  
Specific Protein ◽  
Single Amino Acid ◽  
Amyloid Formation ◽  
Amino Acid Residues ◽  
Proteolytic Fragment ◽  
The Core ◽  
N Terminus ◽  
In Cis

AbstractThe pigment cell-specific protein PMEL forms a functional amyloid matrix in melanosomes onto which the pigment melanin is deposited. The amyloid core consists of a short proteolytic fragment, which we have termed the core-amyloid fragment (CAF) and perhaps additional parts of the protein, such as the PKD domain. A highly O-glycosylated repeat (RPT) domain also derived from PMEL proteolysis associates with the amyloid and is necessary to establish the sheet-like morphology of the assemblies. Excluded from the aggregate is the regulatory N-terminus, which nevertheless must be linked in cis to the CAF in order to drive amyloid formation. The domain is then likely cleaved away immediately before, during, or immediately after the incorporation of a new CAF subunit into the nascent amyloid. We had previously identified a 21 amino acid long region, which mediates the regulatory activity of the N-terminus towards the CAF. However, many mutations in the respective segment caused misfolding and/or blocked PMEL export from the endoplasmic reticulum, leaving their phenotype hard to interpret. Here, we employ a saturating mutagenesis approach targeting the motif at single amino acid resolution. Our results confirm the critical nature of the PMEL N-terminal region and identify several residues essential for PMEL amyloidogenesis.

scholarly journals INFLUENCE OF POLIGUANIDINE ON THE SELF-ORGANIZATION PROCESS IN CYSTEINE-SILVER SOLUTION

2021 ◽  
pp. 69-79
Author(s):  
Анна Нориковна Адамян ◽  
Алена Константиновна Кучурова ◽  
Александра Ивановна Иванова ◽  
Максим Дмитриевич Малышев ◽  
Виктор Анатольевич Герасин ◽  
...  
Keyword(s):  
Guanidine Hydrochloride ◽  
Self Organization ◽  
Silver Acetate ◽  
High Antimicrobial Activity ◽  
Antibacterial Studies ◽  
Polyhexamethylene Guanidine ◽  
Silver Solution ◽  
Organization Process ◽  
Spatial Grid ◽  
Test Cultures

Выполнены реологические, структурные и антибактериальные исследования гидрогелей, получаемых на основе L-цистеина, ацетата серебра и полигексаметиленгуанидин гидрохлорида (ПГМГ-ГХ). Установлено, что водные растворы на основе L-цистеина и ацетата серебра хорошо смешиваются с водным раствором ПГМГ-ГХ, образуя прозрачные гидрогели. Предложена модель строения пространственной сетки геля. Показана высокая антимикробная активность гидрогеля по отношению к тест-культурам патогенных и условно-патогенных микроорганизмов. Rheological, structural, and antibacterial studies of hydrogels based on L-cysteine, silver acetate, and polyhexamethylene guanidine hydrochloride (PHMG-GC) have been carried out. It was found that aqueous solutions based on L-cysteine and silver acetate mix well with an aqueous solution of PHMG-GC, forming transparent hydrogels. A model of the structure of the spatial grid of the gel is proposed. High antimicrobial activity of the hydrogel was shown in relation to test cultures of pathogenic and opportunistic microorganisms.

N-Terminal 33 Amino Acid Residues ofEscherichia coliRecA Protein Contribute to its Self-assembly

1995 ◽  
Vol 250 (4) ◽  
pp. 471-483 ◽  
Author(s):  
Tsutomu Mikawa ◽  
Ryoji Masui ◽  
Tomoko Ogawa ◽  
Hideyuki Ogawa ◽  
Seiki Kuramitsu
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Amino Acid Residues

Mimicking the Function of Eggshell Matrix Proteins: The Role of Multiplets of Charged Amino Acid Residues and Self-Assembly of Peptides in Biomineralization

2005 ◽  
Vol 44 (34) ◽  
pp. 5476-5479 ◽  
Author(s):  
Parayil Kumaran Ajikumar ◽  
Subramanian Vivekanandan ◽  
Rajamani Lakshminarayanan ◽  
Seetharama D. S. Jois ◽  
R. Manjunatha Kini ◽  
...  
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Matrix Proteins ◽  
Amino Acid Residues ◽  
Eggshell Matrix

Amino Acid Residues Vary the Self‐Assembly and Photophysical Properties of Diphenylamine‐Cyanostilbene‐Capped Amphiphiles

ChemPhotoChem ◽  
2020 ◽  
Vol 4 (7) ◽  
pp. 481-486
Author(s):  
Mei‐Yu Yeh ◽  
Tzu‐Yu Tseng ◽  
Hui‐Chun Hsieh ◽  
Bao‐Xing Wu ◽  
Yi‐Shun Liao ◽  
...  
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Photophysical Properties ◽  
The Self ◽  
Amino Acid Residues

Differential supramolecular organisation of Fmoc-dipeptides with hydrophilic terminal amino acid residues by biocatalytic self-assembly

Soft Matter ◽  
2012 ◽  
Vol 8 (45) ◽  
pp. 11565 ◽  
Author(s):  
Meghan Hughes ◽  
Louise S. Birchall ◽  
Karim Zuberi ◽  
Lynsey A. Aitken ◽  
Sisir Debnath ◽  
...  
Keyword(s):  
Amino Acid ◽  
Self Assembly ◽  
Amino Acid Residues ◽  
Terminal Amino Acid ◽  
Supramolecular Organisation ◽  
Terminal Amino

scholarly journals Inhibition of human μ-calpain by conformationally constrained calpastatin peptides

2008 ◽  
Vol 389 (1) ◽  
pp. 83-90 ◽  
Author(s):  
José Pfizer ◽  
Irmgard Assfalg-Machleidt ◽  
Werner Machleidt ◽  
Norbert Schaschke
Keyword(s):  
Amino Acid ◽  
Sequence Alignment ◽  
Salt Bridge ◽  
Side Chain ◽  
Amino Acid Residues ◽  
High Potency ◽  
Conformationally Constrained ◽  
Linear Peptide ◽  
The Core ◽  
Oppositely Charged

Abstract The 27-mer peptide CP1B-[1–27] derived from exon 1B of calpastatin stands out among the known inhibitors for μ- and m-calpain due to its high potency and selectivity. By systematical truncation, a 20-mer peptide, CP1B-[4–23], was identified as the core sequence required to maintain the affinity/selectivity profile of CP1B-[1–27]. Starting with this peptide, the turn-like region Glu10(i)-Leu11(i+1)-Gly12(i+2)-Lys13(i+3) was investigated. Sequence alignment of subdomains 1B, 2B, 3B and 4B from different mammalians revealed that the amino acid residues in position i+1 and i+2 are almost invariably flanked by oppositely charged residues, pointing towards a turn-like conformation stabilized by salt bridge/H-bond interaction. Accordingly, using different combinations of acidic and basic residues in position i and i+3, a series of conformationally constrained variants of CP1B-[4–23] were synthesized by macrolactamization utilizing the side chain functionalities of these residues. With the combination of Glu(i)/Dab(i+3), the maximum of conformational rigidity without substantial loss in affinity/selectivity was reached. These results clearly demonstrate that the linear peptide chain corresponding to subdomain 1B reverses its direction in the region Glu10-Lys13 upon binding to μ-calpain, and thereby adopts a loop-like rather than a tight turn conformation at this site.

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