scholarly journals N-Terminal (1→3)-β-d-Glucan Recognition Proteins from Insects Recognize the Difference in Ultra-Structures of (1→3)-β-d-Glucan

2019 ◽  
Vol 20 (14) ◽  
pp. 3498 ◽  
Author(s):  
Adachi ◽  
Ishii ◽  
Kanno ◽  
Tetsui ◽  
Ishibashi ◽  
...  
Keyword(s):  
Triple Helix ◽  
Solid Phase ◽  
Helical Structure ◽  
Helical Conformation ◽  
Insect Host ◽  
Mealworm Beetle ◽  
Indian Meal ◽  
Recognition Protein ◽  
Human Igg1 ◽  
The Difference

Recognition of (1→3)-β-d-glucans (BGs) by invertebrate β-1,3-d-glucan recognition protein (BGRP) plays a significant role in the activation of Toll pathway and prophenoloxidase systems in insect host defense against fungal invasion. To examine the structure diversity of BGRPs for the recognition of physiochemically different BGs, the binding specificity of BGRPs cloned from four different insects to structure different BGs was characterized using ELISA. Recombinant BGRPs expressed as Fc-fusion proteins of human IgG1 bound to the solid phase of BGs. Based on the binding specificities, the BGRPs were categorized into two groups with different ultrastructures and binding characters; one group specifically binds BGs with triple-helical conformation, while the other group recognizes BGs with disordered conformations like single-helical or partially opened triple helix. The BGRPs from the silkworm and the Indian meal moth bound to the BGs with a triple-helical structure, whereas BGRPs from the red flour beetle and yellow mealworm beetle showed no binding to triple-helical BGs, but bound to alkaline-treated BGs that have a partially opened triple-helical conformation. This evidence suggests that the insect BGRPs can distinguish between different conformations of BGs and are equipped for determining the diversity of BG structures.

scholarly journals N-Terminal (1→3)-β-D-glucan Recognition Proteins from Insects Recognize the Difference in ultra-Structures of (1→3)-β-D-glucan

2019 ◽  
Author(s):  
Yoshiyuki Adachi ◽  
Masaki Ishii ◽  
Takashi Kanno ◽  
Junko Tetsui ◽  
Ken-ichi Ishibashi ◽  
...  
Keyword(s):  
Solid Phase ◽  
Structural Diversity ◽  
Helical Structure ◽  
Phenol Oxidase ◽  
Helical Conformation ◽  
Mealworm Beetle ◽  
Indian Meal ◽  
Recognition Protein ◽  
Human Igg1 ◽  
The Difference

The recognition of (1→3)-β-D-glucans (BGs) by β-1,3-D-glucan recognition protein (BGRP) found in invertebrates plays a significant role in the activation of toll pathway and pro-phenol oxidase system in insect host defense against fungal invasion. To examine the structural diversity of BGs in BGRP interaction, the binding specificity of BGRPs cloned from four different insectswas characterized using ELISA. Recombinant BGRPs expressed as Fc-fusion proteins of human IgG1 bound to solid phase BGs. Because of the binding specificities, the BGRPs were categorized into two different ultrastructure- binding characters. The BGRPs from Silkworm and Indian meal moth bound to BGs containing triple-helical structure. Other BGRPs from red flour beetle and yellow mealworm beetle showed no binding to triple-helical BGs, but to alkaline-treated BGs, which have partially opened helical conformation. These evidences suggest that the innate immune system distinguishes different BG conformations and it is equipped for the diversity of BG structures.

scholarly journals Naphthalimide-Containing BP100 Leads to Higher Model Membranes Interactions and Antimicrobial Activity

Biomolecules ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 542
Author(s):  
Gustavo Penteado Battesini Carretero ◽  
Greice Kelle Viegas Saraiva ◽  
Magali Aparecida Rodrigues ◽  
Sumika Kiyota ◽  
Marcelo Porto Bemquerer ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Biological Activities ◽  
Biological Effects ◽  
Membrane Surface ◽  
Helical Structure ◽  
Helical Conformation ◽  
Property A ◽  
Cellular Processes ◽  
Double Stranded Dna ◽  
Low Toxicity

In a large variety of organisms, antimicrobial peptides (AMPs) are primary defenses against pathogens. BP100 (KKLFKKILKYL-NH2), a short, synthetic, cationic AMP, is active against bacteria and displays low toxicity towards eukaryotic cells. BP100 acquires a α-helical conformation upon interaction with membranes and increases membrane permeability. Despite the volume of information available, the action mechanism of BP100, the selectivity of its biological effects, and possible applications are far from consensual. Our group synthesized a fluorescent BP100 analogue containing naphthalimide linked to its N-terminal end, NAPHT-BP100 (Naphthalimide-AAKKLFKKILKYL-NH2). The fluorescence properties of naphthalimides, especially their spectral sensitivity to microenvironment changes, are well established, and their biological activities against transformed cells and bacteria are known. Naphthalimide derived compounds are known to interact with DNA disturbing related processes as replication and transcription, and used as anticancer agents due to this property. A wide variety of techniques were used to demonstrate that NAPHT-BP100 bound to and permeabilized zwitterionic POPC and negatively charged POPC:POPG liposomes and, upon interaction, acquired a α-helical structure. Membrane surface high peptide/lipid ratios triggered complete permeabilization of the liposomes in a detergent-like manner. Membrane disruption was driven by charge neutralization, lipid aggregation, and bilayer destabilization. NAPHT-BP100 also interacted with double-stranded DNA, indicating that this peptide could also affect other cellular processes besides causing membrane destabilization. NAPHT-BP100 showed increased antibacterial and hemolytic activities, compared to BP100, and may constitute an efficient antimicrobial agent for dermatological use. By conjugating BP100 and naphthalimide DNA binding properties, NAPHT-BP100 bound to a large extent to the bacterial membrane and could more efficiently destabilize it. We also speculate that peptide could enter the bacteria cell and interact with its DNA in the cytoplasm.

scholarly journals Changes in Phenols, Polysaccharides and Volatile Profiles of Noni (Morinda citrifolia L.) Juice during Fermentation

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2604
Author(s):  
Zhulin Wang ◽  
Rong Dou ◽  
Ruili Yang ◽  
Kun Cai ◽  
Congfa Li ◽  
...  
Keyword(s):  
Octanoic Acid ◽  
Solid Phase ◽  
Principal Component ◽  
Hexanoic Acid ◽  
Morinda Citrifolia ◽  
Gas Chromatography Mass Spectrometry ◽  
Aroma Characteristics ◽  
Volatile Profiles ◽  
The Difference ◽  
Aroma Components

The change in phenols, polysaccharides and volatile profiles of noni juice from laboratory- and factory-scale fermentation was analyzed during a 63-day fermentation process. The phenol and polysaccharide contents and aroma characteristics clearly changed according to fermentation scale and time conditions. The flavonoid content in noni juice gradually increased with fermentation. Seventy-three volatile compounds were identified by solid-phase microextraction coupled with gas chromatography–mass spectrometry (SPME-GC-MS). Methyl hexanoate, 3-methyl-3-buten-1-ol, octanoic acid, hexanoic acid and 2-heptanone were found to be the main aroma components of fresh and fermented noni juice. A decrease in octanoic acid and hexanoic acid contents resulted in the less pungent aroma in noni juice from factory-scale fermentation. The results of principal component analysis of the electronic nose suggested that the difference in nitrogen oxide, alkanes, alcohols, and aromatic and sulfur compounds, contributed to the discrimination of noni juice from different fermentation times and scales.

scholarly journals Secondary structure and biophysical activity of synthetic analogues of the pulmonary surfactant polypeptide SP-C

1995 ◽  
Vol 307 (2) ◽  
pp. 535-541 ◽  
Author(s):  
J Johansson ◽  
G Nilsson ◽  
R Strömberg ◽  
B Robertson ◽  
H Jörnvall ◽  
...  
Keyword(s):  
Secondary Structure ◽  
Pulmonary Surfactant ◽  
Transmembrane Helix ◽  
Helical Structure ◽  
Helical Conformation ◽  
Synthetic Analogues ◽  
Charged Amino Acids ◽  
Phospholipid Micelles ◽  
Helical Content ◽  
Biophysical Activity

Native pulmonary-surfactant-associated lipopolypeptide SP-C, its chemically depalmitoylated form and several synthetic analogues lacking the palmitoylcysteine residues were analysed for secondary structure in phospholipid micelles and for biophysical activity in 1,2-dipalmitoyl-sn-glycero-3- phosphocholine/phosphatidylglycerol/palmitic acid (68:22:9, by wt.). Compared with the native molecule, with the entire poly-valyl part in a known alpha-helical conformation, depalmitoylated SP-C was found to be still mainly alpha-helical, but with an approx. 20% decrease in the helical content. A synthetic hybrid polypeptide where the entire poly-valyl alpha-helical part of native SP-C had been replaced with the amino acid sequence of a transmembrane helix of bacteriorhodopsin is also predominantly alpha-helical. In contrast, synthetic SP-C analogues lacking only the palmitoyl groups, by replacement of the palmitoylcysteine residues with cysteine, phenylalanine or serine, or lacking the positively charged amino acids by replacement with alanine, are considerably less alpha-helical than both native and depalmitoylated SP-C. The data indicate that the SP-C palmitoyl groups are important for maintenance of the alpha-helical conformation in parts of the polypeptide, and that the poly-valyl alpha-helical conformation is not fully formed in synthetic SP-C polypeptides. Furthermore, the helical structure of both native and depalmitoylated SP-C in dodecylphosphocholine micelles is very resistant to thermal denaturation, exhibiting ordered structure at 90 degrees C. The alpha-helical content grossly parallels the peptide-induced acceleration of the spreading of phospholipids at an air/water interface and the increase of surface pressure. The data suggest that the alpha-helical conformation itself, rather than just the covalent structure, is of prime importance for the biological function of synthetic pulmonary-surfactant peptides.

Trapping Effect on the Kinetic Critical Radius in Nucleation and Growth Processes

2014 ◽  
Vol 790-791 ◽  
pp. 97-102
Author(s):  
Zoltán Erdélyi ◽  
Zoltán Balogh ◽  
Gabor L. Katona ◽  
Dezső L. Beke
Keyword(s):  
Critical Nucleus ◽  
Solid Phase ◽  
Kinetic Monte Carlo ◽  
Mean Field ◽  
Transformation Process ◽  
Nucleus Size ◽  
Critical Nucleus Size ◽  
Acta Mater ◽  
Order Of Magnitude ◽  
The Difference

The critical nucleus size—above which nuclei grow, below dissolve—during diffusion controlled nucleation in binary solid-solid phase transformation process is calculated using kinetic Monte Carlo (KMC). If atomic jumps are slower in an A-rich nucleus than in the embedding B-rich matrix, the nucleus traps the A atoms approaching its surface. It doesn’t have enough time to eject A atoms before new ones arrive, even if it would be favourable thermodynamically. In this case the critical nucleus size can be even by an order of magnitude smaller than expected from equilibrium thermodynamics or without trapping. These results were published in [Z. Erdélyi et al., Acta Mater. 58 (2010) 5639]. In a recent paper M. Leitner [M. Leitner, Acta Mater. 60 (2012) 6709] has questioned our results based on the arguments that his simulations led to different results, but he could not point out the reason for the difference. In this paper we summarize our original results and on the basis of recent KMC and kinetic mean field (KMF) simulations we show that Leitner’s conclusions are not valid and we confirm again our original results.

scholarly journals NMR structure of the water soluble Aβ17–34 peptide

2014 ◽  
Vol 34 (6) ◽  
Author(s):  
Genadiy Fonar ◽  
Abraham O. Samson
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Nicotinic Acetylcholine Receptors ◽  
Neurodegenerative Disorder ◽  
Amyloid Β ◽  
Helical Structure ◽  
Nmr Structure ◽  
Water Soluble ◽  
Helical Conformation ◽  
Aβ Amyloid

Alzheimer's disease is the most common neurodegenerative disorder in the world. Its most significant symptoms are memory loss and decrease in cognition. Alzheimer's disease is characterized by aggregation of two proteins in the brain namely Aβ (amyloid β) and tau. Recent evidence suggests that the interaction of soluble Aβ with nAChR (nicotinic acetylcholine receptors) contributes to disease progression. In this study, we determine the NMR structure of an Aβ17–34 peptide solubilized by the addition of two glutamic acids at each terminus. Our results indicate that the Aβ peptide adopts an α-helical structure for residues 19–26 and 28–33. The α-helical structure is broken around residues S26, N27 and K28, which form a kink in the helical conformation. This α-helix was not described earlier in an aqueous solution without organic solvents, and at physiological conditions (pH 7). These data are in agreement with Aβ adopting an α-helical conformation in the membrane before polymerizing into amyloid β-sheets and provide insight into the intermediate state of Aβ in Alzheimer's disease.

scholarly journals Structural diversity and domain composition of a unique collagenous fragment (intima collagen) obtained from human placenta

1983 ◽  
Vol 211 (2) ◽  
pp. 295-302 ◽  
Author(s):  
E Odermatt ◽  
J Risteli ◽  
V van Delden ◽  
R Timpl
Keyword(s):  
Human Placenta ◽  
Triple Helix ◽  
Structural Diversity ◽  
Helical Conformation ◽  
Basic Unit ◽  
Bacterial Collagenase ◽  
Disulphide Bonds ◽  
Triple Helices ◽  
Electron Microscopical ◽  
Polypeptide Chains

Intima collagen was obtained from pepsin digests of human placenta in two forms, which differ to some extent in the size of their constituent polypeptide chains (Mr 50 000-70 000). These chains are connected by disulphide bonds to large aggregates. The aggregates are arranged in a triple-helical conformation with a remarkably high thermal stability (Tm 41-62 degrees C) and are resistant to further proteolytic digestion. Reduction of as little as 5% of the disulphide bonds produces mainly monomeric triple helices (Mr about 160 000) with Tm 32 degrees C. Partially reduced material can be separated into triple-helical and non-collagenous domains by proteolysis. Pepsin releases a collagenous component with chains of Mr 38 000. Bacterial collagenase liberates two non-collagenous segments (Mr 15 000-30 000) rich in cystine. Treatment with collagenase before reduction separates intima collagen into a large fragment composed of collagenous (Tm 41 degrees C) and non-collagenous structures and a single non-collagenous segment. The data support the electron-microscopical model of intima collagen [Furthmayr, Wiedemann, Timpl, Odermatt & Engel (1983) Biochem. J. 211, 303-311], indicating that the basic unit of the fragment consists of a continuous triple helix joining two globular domains.

Introduction — a retrospective viewpoint

1999 ◽  
Author(s):  
R. C. Sheppard
Keyword(s):  
Peptide Synthesis ◽  
Solid Phase ◽  
Chemical Society ◽  
Benzyl Ester ◽  
Heterogeneous Reactions ◽  
New Technique ◽  
Annual Reports ◽  
Coupling Reactions ◽  
Peptide Chemistry ◽  
The Difference

The Chemical Society publication Annual Reports on the Progress of Chemistry for 1963 attempted to inform readers of all the highly significant advances in all the major fields of pure chemistry during that year. Fortunately, the section on peptide chemistry drew attention to a paper by R. B. Merrifield which had just been published in the Journal of the American Chemical Society: A novel approach to peptide synthesis has been the use of a chloromethylated polystyrene polymer as an insoluble but porous solid phase on which the coupling reactions are carried out. Attachment to the polymer constitutes protection of the carboxyl group (as a modified benzyl ester), and the peptide is lengthened from its amino-end by successive carbodiimide couplings. The method has been applied to the synthesis of a tetrapeptide, but incomplete reactions lead to the accumulation of by products. Further development of this interesting method is awaited. I remember thinking at the time that in this paper we had possibly seen both the beginning and the end of the interesting new technique of solid phase peptide synthesis. To many organic chemists, the described result was that anticipated—difficulty in bringing heterogeneous reactions to completion resulting in impure products. Both this and purification problems were expected to worsen as the chain length was increased beyond Merrifield’s tetrapeptide limit. In fact, I probably had at the time an inadequate appreciation of the difference between truly heterogeneous or surface reactions and those in the solvated gel phase. The latter approaches much more closely the solution situation. However, the new technique also flouted many of the basic principles of contemporary organic synthesis which required rigorous isolation, purification, and characterization regimes following each synthetic step. In Merrifield’s new technique, isolation consisted simply of washing the solid resin, there was no other purification of the products of each reaction, and little or no characterization of resin-bound intermediates was attempted. The first two of these are of course the important characteristics which give the method its speed and simplicity and contribute to its efficiency. Small wonder, though, that in many minds there was doubt about the future of the new technique.

Barrier Properties of Electroless Ni-B UBM for Solder Joining

2015 ◽  
Vol 2015 (1) ◽  
pp. 000862-000867
Author(s):  
Masaru Morita ◽  
Toshiya Akamatsu ◽  
Nobuhiro Imaizumi ◽  
Seiki Sakuyama
Keyword(s):  
Integrated Circuits ◽  
High Speed ◽  
Solid Phase ◽  
Barrier Properties ◽  
Electrode Structure ◽  
Phase Diffusion ◽  
3D Ics ◽  
The Difference ◽  
Electroless Ni ◽  
Plating Layer

As demands accelerate for high density, high speed transmission and low power integrated circuits, 3D-ICs with through-silicon via (TSV) is pursued. In the structure of 3D-ICs, the first die is attached to the second die with micro bump, and the second die is attached to the circuit substrate with a C4 solder bump. The electrode structure of the second die is Cu/Ni UBM. The stress of the Ni-B layer is less than that of the Ni-P layer, and the Ni-B layer can suppress stress and die warpage. The purposes of our study are to clarify the difference in the barrier properties of the Ni-B UBM and Ni-P under bump metal (UBM) and the relevance of the barrier properties of Ni UBM and intermetallic compound (IMC) growth. It was found that an electroless Ni-B plating layer is superior to a Ni-P plating layer for UBM in liquid phase diffusion and in solid phase diffusion, and that a segregated B layer is formed under the IMC layer of a Ni-B land due to reflow soldering. It was estimated that this B layer plays the role of being a barrier layer for solder diffusion.

Mechanism of Stress-Enhanced Solid-Phase Epitaxy

1991 ◽  
Vol 237 ◽  
Author(s):  
T. K. Chaki
Keyword(s):  
Hydrostatic Pressure ◽  
Point Defects ◽  
Solid Phase ◽  
Amorphous Solid ◽  
Amorphous Layer ◽  
Crystalline Phases ◽  
Self Diffusion ◽  
Bending Stresses ◽  
Enhanced Mobility ◽  
The Difference

ABSTRACTEnhancement of solid-phase epitaxial growth (SPEG) due to hydrostatic pressures and bending stresses is explained by stress-enhanced mobility of point defects in the amorphous solid. The crystallization is by the adjustment of atomic positions in the vicinity of the crystallization/amorphous (c-a) interface due to self-diffusion in the amorphous phase, assisted by a free energy decrease equal to the difference in free energies between the amorphous and crystalline phases. Due to a mismatch in the bulk moduli between the amorphous and crystalline phases, the application of a hydrostatic pressure can develop tensile stresses in the amorphous layer near the c-a interface. Non-hydrostatic stresses in the amorphous layer enhance the mobility of point defects in the amorphous layer and, therefore, an enhancement of the SPEG rate. In the cases of both hydrostatic pressure and bending, the enhancement occurs in the tensile side, indicating that vacancy-like mechanism is predominant in SPEG.

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