scholarly journals Chiroptical Properties and Conformation of Four Lasiocepsin-Related Antimicrobial Peptides: Structural Role of Disulfide Bridges

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 812
Author(s):  
Markéta Pazderková ◽  
Václav Profant ◽  
Petr Maloň ◽  
Rina K. Dukor ◽  
Václav Čeřovský ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Tertiary Structure ◽  
Sodium Dodecyl ◽  
Disulfide Bridge ◽  
Biological Properties ◽  
Disulfide Bridges ◽  
Supporting Function ◽  
Bridge Pattern ◽  
Peptide Secondary Structure

We report an investigation of the role of disulfide bridges in the 27-residue antimicrobial peptide lasiocepsin (I) containing two disulfide groups (Cys8–Cys25, Cys17–Cys27) and three its analogs lacking one (II, III) or both (IV) native disulfides. Selective alternate incorporation of one or both disulfide bridges influences symmetry, conformation and biological properties of these peptides as demonstrated in their chiroptical (particularly Raman) properties. The effect of modifying the disulfide bridge pattern on the peptide secondary structure is investigated in water and in the presence of 2,2,2-trifluoroethanol and sodium dodecyl sulphate. A combination of experimental electronic and vibrational chiroptical data shows that both disulfide groups are necessary for stabilizing lasiocepsin secondary structure. While the Cys8–Cys25 disulfide group is important for sustaining lasiocepsin tertiary structure and maintaining its biological activity, the Cys17–Cys27 disulfide bridge has a supporting function consisting in reducing peptide flexibility.

scholarly journals Binding of CML-Modified as Well as Heat-Glycated β-lactoglobulin to Receptors for AGEs Is Determined by Charge and Hydrophobicity

2020 ◽  
Vol 21 (12) ◽  
pp. 4567 ◽  
Author(s):  
Hannah E. Zenker ◽  
Malgorzata Teodorowicz ◽  
Arifa Ewaz ◽  
R.J. Joost van Neerven ◽  
Huub F.J. Savelkoul ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Tertiary Structure ◽  
Glyoxylic Acid ◽  
Native Page ◽  
Galectin 3 ◽  
Carboxymethyl Lysine ◽  
Antigen Presenting ◽  
Age Receptors ◽  
Β Lactoglobulin

Intake of dietary advanced glycation end products (AGEs) is associated with inflammation-related health problems. Nε-carboxymethyl lysine (CML) is one of the best characterised AGEs in processed food. AGEs have been described as ligands for receptors present on antigen presenting cells. However, changes in protein secondary and tertiary structure also induce binding to AGE receptors. We aimed to discriminate the role of different protein modifications in binding to AGE receptors. Therefore, β-lactoglobulin was chemically modified with glyoxylic acid to produce CML and compared to β-lactoglobulin glycated with lactose. Secondary structure was monitored with circular dichroism, while hydrophobicity and formation of β-sheet structures was measured with ANS-assay and ThT-assay, respectively. Aggregation was monitored using native-PAGE. Binding to sRAGE, CD36, and galectin-3 was measured using inhibition ELISA. Even though no changes in secondary structure were observed in all tested samples, binding to AGE receptors increased with CML concentration of CML-modified β-lactoglobulin. The negative charge of CML was a crucial determinant for the binding of protein bound CML, while binding of glycated BLG was determined by increasing hydrophobicity. This shows that sRAGE, galectin-3, and CD36 bind to protein bound CML and points out the role of negatively charged AGEs in binding to AGE receptors.

Complete Primary Structure of Prothrombin. Partial Primary Structures oí Plasminogen and Hirudin

1975 ◽  
Author(s):  
S. Magnusson ◽  
L. Sottrup-Jensen ◽  
H. Glaeys ◽  
M. Zajdel ◽  
T. E. Petersen
Keyword(s):  
Heavy Chain ◽  
Primary Structure ◽  
General Structure ◽  
Factor Xa ◽  
Disulfide Bridge ◽  
Disulfide Bridges ◽  
Pancreatic Secretory Trypsin Inhibitor ◽  
Carboxyglutamic Acid ◽  
Bridge Pattern ◽  
Sequence Similarities

The complete amino acid sequence (582 residues), positions of the twelve disulfide bridges and three carbohydrate substituents, position and identity of the ten vitamin Independent γ-carboxyglutamic acid (Gla) residues has been determined. A synthetic substrate specific for Factor Xa has been developed on the basis of the prothrombin structure. The primary structure of hirudin has been nearly completed and suggests a mechanism for its thrombin specificity.The pro-part of prothrombin contains two 83 residue regions with identical disulfide-bridge pattern and 31 sequence identities. These “kringle” structures show sequence similarities with the pancreatic secretory trypsin inhibitor and hirudin. A chymotryptic digest of CM-plasminogen was investigated to find the heavy chain-light chain overlap region. This was isolated and sequenced (28 from h.c., 10 from l.c.) to study the specificity of plasminogen activators. From the same digest sequence evidence has been obtained which indicates that the heavy chain part of plasmin consists mainly of four kringle structures like the two in prothrombin, suggesting a common general structure and evolutionary origin of these two large zymogen structures.

scholarly journals Effect of monovalent salt concentration and peptide secondary structure in peptide-micelle binding

RSC Advances ◽  
2021 ◽  
Vol 11 (58) ◽  
pp. 36836-36849
Author(s):  
Suvankar Ghosh ◽  
Gopal Pandit ◽  
Swapna Debnath ◽  
Sunanda Chatterjee ◽  
Priyadarshi Satpati
Keyword(s):  
Secondary Structure ◽  
Salt Concentration ◽  
Salt Sensitivity ◽  
Membrane Mimetic ◽  
Monovalent Salt ◽  
Peptide Secondary Structure

We report computational (∼14.2 μs of MD) and experimental (CD, fluorescence) investigations to examine the salt-sensitivity and the role of the peptide secondary structure on LL-14 binding to simple membrane mimetic systems.

Green synthesis of silver nanoparticles using sustainable resources and their use as antibacterial agents: A review

2020 ◽  
Vol 13 ◽  
Author(s):  
Kumari Jyoti ◽  
Punyasloka Pattnaik ◽  
Tej Singh
Keyword(s):  
Silver Nanoparticles ◽  
Plant Extracts ◽  
Metallic Nanoparticles ◽  
Cost Effective ◽  
Biological Properties ◽  
Metal Species ◽  
Sustainable Resources ◽  
Research Areas ◽  
Low Toxicity

Background:: Synthesis of metallic nanoparticles has attracted extensive vitality in numerous research areas such as drug delivery, biomedicine, catalysis etc. where continuous efforts are being made by scientists and engineers to investigate new dimensions for both technological and industrial advancements. Amongst numerous metallic nanoparticles, silver nanoparticle (AgNPs) is a novel metal species with low toxicity, higher stability and significant chemical, physical and biological properties. Methods:: In this, various methods for the fabrication of AgNPs are summarized. Importantly, we concentrated on the role of reducing agents of different plants parts, various working conditions such as AgNO3 concentration; ratio of AgNO3/extract; incubation time; centrifugal conditions, size and shapes. Results:: This study suggested that eco-friendly and non toxic biomolecules present in the extracts (e.g. leaf, stem and root) of plants are used as reducing and capping agents for silver nanoparticles fabrication. This method of fabrication of silver nanoparticles using plants extracts is comparatively cost-effective and simple. A silver salt is simply reduced by biomolecules present in the extracts of these plants. In this review, we have emphasized the synthesis and antibacterial potential of silver nanoparticles using various plant extracts. Conclusion:: Fabrication of silver nanoparticles using plant extracts have advantage over the other physical methods, as it is safe, eco-friendly and simple to use. Plants have huge potential for the fabrication of silver nanoparticles of wide potential of applications with desired shape and size.

Physical and Biological Properties and Principles

2018 ◽  
Keyword(s):  
Biological Properties ◽  
Animal Locomotion ◽  
The Media ◽  
Key Dimensions ◽  
Scaling Analyses ◽  
Physical Principles

Studies of animal locomotion are grounded in an understanding of the physical principles that govern how animals move and properties of the media through which they move. These studies, in turn, explain why certain biological devices, such as a wing or a fin, share features that have evolved for movement within their particular fluid environments. In this chapter, we examine the role of the environment and the fundamentals of loading and forces in animal mechanics. We offer a quick review of scaling analyses as well as the key dimensions and units used in this book to assist with your appreciation of the information.

scholarly journals Investigating the Feasibility of Mefenamic Acid Nanosuspension for Pediatric Delivery: Preparation, Characterization, and Role of Excipients

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 574
Author(s):  
Nikhat Perween ◽  
Sultan Alshehri ◽  
T. S. Easwari ◽  
Vivek Verma ◽  
Md. Faiyazuddin ◽  
...  
Keyword(s):  
Particle Size ◽  
Mefenamic Acid ◽  
Hydroxypropyl Methylcellulose ◽  
Sodium Dodecyl ◽  
Aqueous Solubility ◽  
Oral Route ◽  
Precipitation Method ◽  
Antisolvent Precipitation

Molecules with poor aqueous solubility are difficult to formulate using conventional approaches and are associated with many formulation delivery issues. To overcome these obstacles, nanosuspension technology can be one of the promising approaches. Hence, in this study, the feasibility of mefenamic acid (MA) oral nanosuspension was investigated for pediatric delivery by studying the role of excipients and optimizing the techniques. Nanosuspensions of MA were prepared by adopting an antisolvent precipitation method, followed by ultrasonication with varying concentrations of polymers, surfactants, and microfluidics. The prepared nanosuspensions were evaluated for particle size, morphology, and rheological measures. Hydroxypropyl methylcellulose (HPMC) with varying concentrations and different stabilizers including Tween® 80 and sodium dodecyl sulfate (SLS) were used to restrain the particle size growth of the developed nanosuspension. The optimized nanosuspension formula was stable for more than 3 weeks and showed a reduced particle size of 510 nm with a polydispersity index of 0.329. It was observed that the type and ratio of polymer stabilizers were responsive on the particle contour and dimension and stability. We have developed a biologically compatible oral nanoformulation for a first-in-class drug beautifully designed for pediatric delivery that will be progressed toward further in vivo enabling studies. Finally, the nanosuspension could be considered a promising carrier for pediatric delivery of MA through the oral route with enhanced biological impact.

RNA secondary structure dependence in METTL3–METTL14 mRNA methylation is modulated by the N-terminal domain of METTL3

2020 ◽  
Vol 402 (1) ◽  
pp. 89-98
Author(s):  
Nathalie Meiser ◽  
Nicole Mench ◽  
Martin Hengesbach
Keyword(s):  
Secondary Structure ◽  
Rna Binding ◽  
Specific Protein ◽  
Structure Dependence ◽  
Terminal Domain ◽  
Methylation Assay ◽  
A Site ◽  
Methylation Activity

AbstractN6-methyladenosine (m6A) is the most abundant modification in mRNA. The core of the human N6-methyltransferase complex (MTC) is formed by a heterodimer consisting of METTL3 and METTL14, which specifically catalyzes m6A formation within an RRACH sequence context. Using recombinant proteins in a site-specific methylation assay that allows determination of quantitative methylation yields, our results show that this complex methylates its target RNAs not only sequence but also secondary structure dependent. Furthermore, we demonstrate the role of specific protein domains on both RNA binding and substrate turnover, focusing on postulated RNA binding elements. Our results show that one zinc finger motif within the complex is sufficient to bind RNA, however, both zinc fingers are required for methylation activity. We show that the N-terminal domain of METTL3 alters the secondary structure dependence of methylation yields. Our results demonstrate that a cooperative effect of all RNA-binding elements in the METTL3–METTL14 complex is required for efficient catalysis, and that binding of further proteins affecting the NTD of METTL3 may regulate substrate specificity.

scholarly journals Physicochemical characterisation of kafirins extracted from sorghum grain and dried distillers grain with solubles related to their biomaterial functionality

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Umar Shah ◽  
Deepak Dwivedi ◽  
Mark Hackett ◽  
Hani Al-Salami ◽  
Ranjeet P. Utikar ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Physicochemical Properties ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Chemical Properties ◽  
X Ray ◽  
Distillers Grain ◽  
Sorghum Grain ◽  
Dried Distillers Grain ◽  
Polypeptide Profile

AbstractKafirin, the hydrophobic prolamin storage protein in sorghum grain is enriched when the grain is used for bioethanol production to give dried distillers grain with solubles (DGGS) as a by-product. There is great interest in DDGS kafirin as a new source for biomaterials. There is however a lack of fundamental understanding of how the physicochemical properties of DDGS kafirin having been exposed to the high temperature conditions during ethanol production, compare to kafirin made directly from the grain. An understanding of these properties is required to catalyse the utilisation of DDGS kafirin for biomaterial applications. The aim of this study was to extract kafirin directly from sorghum grain and from DDGS derived from the same grain and, then perform a comparative investigation of the physicochemical properties of these kafirins in terms of: polypeptide profile by sodium-dodecyl sulphate polyacrylamide gel electrophoresis; secondary structure by Fourier transform infra-red spectroscopy and x-ray diffraction, self-assembly behaviour by small-angle x-ray scattering, surface morphology by scanning electron microscopy and surface chemical properties by energy dispersive x-ray spectroscopy. DDGS kafirin was found to have very similar polypeptide profile as grain kafirin but contained altered secondary structure with increased levels of β-sheets. The structure morphology showed surface fractals and surface elemental composition suggesting enhanced reactivity with possibility to endow interfacial wettability. These properties of DDGS kafirin may provide it with unique functionality and thus open up opportunities for it to be used as a novel food grade biomaterial.

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