scholarly journals Split Enzyme-Based Biosensors for Structural Characterization of Soluble and Insoluble β-Glucans

2021 ◽  
Vol 22 (4) ◽  
pp. 1576
Author(s):  
Daisuke Yamanaka ◽  
Suzuka Kurita ◽  
Yuka Hanayama ◽  
Yoshiyuki Adachi
Keyword(s):  
Chain Structure ◽  
Side Chain ◽  
Dependent Manner ◽  
Close Proximity ◽  
Recognition Protein ◽  
Split Luciferase Complementation ◽  
Time Changes ◽  
Function Relationship ◽  
Relationship Of ◽  
Long Chain

β-Glucan is widely distributed in various plants and microorganisms and is composed of β-1,3-linked d-glucose units. It may have a branched short or long side chain of glucose units with β-1,6- or β-1,4-linkage. Numerous studies have investigated different β-glucans and revealed their bioactivities. To understand the structure-function relationship of β-glucan, we constructed a split-luciferase complementation assay for the structural analysis of long-chain β-1,6-branched β-1,3-glucan. The N- and C-terminal fragments of luciferase from deep-sea shrimp were fused to insect-derived β-1,3-glucan recognition protein and fungal endo-β-1,6-glucanase (Neg1)-derived β-1,6-glucan recognition protein, respectively. In this approach, two β-glucan recognition proteins bound to β-glucan molecules come into close proximity, resulting in the assembly of the full-length reporter enzyme and induction of transient luciferase activity, indicative of the structure of β-glucan. To test the applicability of this assay, β-glucan and two β-glucan recognition proteins were mixed, resulting in an increase in the luminescence intensity in a β-1,3-glucan with a long polymer of β-1,6-glucan in a dose-dependent manner. This simple test also allows the monitoring of real-time changes in the side chain structure and serves as a convenient method to distinguish between β-1,3-glucan and long-chain β-1,6-branched β-1,3-glucan in various soluble and insoluble β-glucans.

Conformation−Function Relationship of Vitamin D:  Conformational Analysis Predicts Potential Side-Chain Structure

1998 ◽  
Vol 41 (9) ◽  
pp. 1467-1475 ◽  
Author(s):  
Sachiko Yamada ◽  
Keiko Yamamoto ◽  
Hiroyuki Masuno ◽  
Masateru Ohta
Keyword(s):  
Vitamin D ◽  
Conformational Analysis ◽  
Chain Structure ◽  
Side Chain ◽  
Function Relationship ◽  
Relationship Of

scholarly journals Relationship of 25-hydroxyvitamin D3 side chain structure to biological activity.

1975 ◽  
Vol 250 (1) ◽  
pp. 226-230
Author(s):  
M F Holick ◽  
M Garabedian ◽  
H K Schnoes ◽  
H F DeLuca
Keyword(s):  
Biological Activity ◽  
Chain Structure ◽  
Side Chain ◽  
Relationship Of

Structure-function relationship of substrate length specificity of dextran glucosidase from Streptococcus mutans

Biologia ◽  
2008 ◽  
Vol 63 (6) ◽  
Author(s):  
Wataru Saburi ◽  
Hironori Hondoh ◽  
Young-Min Kim ◽  
Haruhide Mori ◽  
Masayuki Okuyama ◽  
...  
Keyword(s):  
Structure Function ◽  
High Activity ◽  
Streptococcus Mutans ◽  
Chain Length ◽  
Structural Elements ◽  
Chain Length Specificity ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Relationship Of ◽  
Long Chain

AbstractDextran glucosidase from Streptococcus mutans (SMDG), an exo-type glucosidase of glycoside hydrolase (GH) family 13, specifically hydrolyzes an α-1,6-glucosidic linkage at the non-reducing ends of isomaltooligosaccharides and dextran. SMDG shows the highest sequence similarity to oligo-1,6-glucosidases (O16Gs) among GH family 13 enzymes, but these enzymes are obviously different in terms of substrate chain length specificity. SMDG efficiently hydrolyzes both short-and long-chain substrates, while O16G acts on only short-chain substrates. We focused on this difference in substrate specificity between SMDG and O16G, and elucidated the structure-function relationship of substrate chain length specificity in SMDG. Crystal structure analysis revealed that SMDG consists of three domains, A, B, and C, which are commonly found in other GH family 13 enzymes. The structural comparison between SMDG and O16G from Bacillus cereus indicated that Trp238, spanning subsites +1 and +2, and short β → α loop 4, are characteristic of SMDG, and these structural elements are predicted to be important for high activity toward long-chain substrates. The substrate size preference of SMDG was kinetically analyzed using two mutants: (i) Trp238 was replaced by a smaller amino acid, alanine, asparagine or proline; and (ii) short β → α loop 4 was exchanged with the corresponding loop of O16G. Mutant enzymes showed lower preference for long-chain substrates than wild-type enzyme, indicating that these structural elements are essential for the high activity toward long-chain substrates, as implied by structural analysis.

scholarly journals Inactivation of yeast inorganic pyrophosphatase by organic solvents

2004 ◽  
Vol 76 (4) ◽  
pp. 699-705 ◽  
Author(s):  
Rodrigo Grazinoli-Garrido ◽  
Mauro Sola-Penna
Keyword(s):  
Organic Solvents ◽  
Unsolved Problem ◽  
Inorganic Pyrophosphatase ◽  
Clear Understanding ◽  
Dependent Manner ◽  
Nonaqueous Enzymology ◽  
Function Relationship ◽  
Relationship Of ◽  
Dose Dependent ◽  
Hydrophobic Solvent

A number of application for enzymes in organic solvents have been developed in chemical processing, food related conversions and analyses. The only unsolved problem related to nonaqueous enzymology is the notion that enzymes in organic solvent are mostly far less active than in water. Therefore, studies concerning the mechanisms by which enzymes are inactivated by organic solvents would reveal a clear understanding of the structure-function relationship of this phenomenon. Here we analyzed the effects of a series of alcohols (methanol, ethanol, 1-propanol and 2-propanol) and acetone on the activity of yeast inorganic pyrophosphatase. We observed that solvents inactivated the enzyme in a dose-dependent manner. This inactivation is also dependent on the hydrophobicity of the solvent, where the most hydrophobic solvent is also the most effective one. The I50 for inactivation by n-alcohols are 5.9±4, 2.7±1 and 2.5±1 M for methanol, ethanol and 1-propanol, respectively. Inactivation was less effective at 37C than at 5C, when the I50 for inactivation by methanol, ethanol and 1-propanol are 4.5±2, 2.1±2 and 1.7±1 M, respectively. Our proposal is that solvent binds to the enzyme structure promoting the inactivation by stabilizing an unfolded structure, and that this binding is through the hydrophobic regions of either the protein or the solvent.

Structure–property–function relationship of fluorescent conjugated microporous polymers

2021 ◽  
Author(s):  
M. G. Monika Bai ◽  
H. Vignesh Babu ◽  
V. Lakshmi ◽  
M. Rajeswara Rao
Keyword(s):  
Long Range ◽  
Structure Property ◽  
Porous Organic Polymers ◽  
Aggregation Induced Emission ◽  
Microporous Polymers ◽  
Exciton Migration ◽  
Wide Range ◽  
Function Relationship ◽  
Relationship Of ◽  
Conjugated Microporous Polymers

Fluorescent porous organic polymers are a unique class of materials owing to their strong aggregation induced emission, long range exciton migration and permanent porosity, thus envisioned to possess a wide range of applications (sensing, OLEDs).

scholarly journals Antimicrobial Peptide Modifications against Clinically Isolated Antibiotic-Resistant Salmonella

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4654
Author(s):  
Suthee Mangmee ◽  
Onrapak Reamtong ◽  
Thareerat Kalambaheti ◽  
Sittiruk Roytrakul ◽  
Piengchan Sonthayanon
Keyword(s):  
Antibacterial Activity ◽  
Hemolytic Activity ◽  
Multidrug Resistant ◽  
Terminal Group ◽  
Scorpion Venom ◽  
Antibiofilm Activity ◽  
Peptide Antibiotic ◽  
Dependent Manner ◽  
C Terminus ◽  
Relationship Of

Antimicrobial peptides are promising molecules to address the global antibiotic resistance problem, however, optimization to achieve favorable potency and safety is required. Here, a peptide-template modification approach was employed to design physicochemical variants based on net charge, hydrophobicity, enantiomer, and terminal group. All variants of the scorpion venom peptide BmKn-2 with amphipathic α-helical cationic structure exhibited an increased antibacterial potency when evaluated against multidrug-resistant Salmonella isolates at a MIC range of 4–8 µM. They revealed antibiofilm activity in a dose-dependent manner. Sheep red blood cells were used to evaluate hemolytic and cell selectivity properties. Peptide Kn2-5R-NH2, dKn2-5R-NH2, and 2F-Kn2-5R-NH2 (variants with +6 charges carrying amidated C-terminus) showed stronger antibacterial activity than Kn2-5R (a variant with +5 charges bearing free-carboxyl group at C-terminus). Peptide dKn2-5R-NH2 (d-enantiomer) exhibited slightly weaker antibacterial activity with much less hemolytic activity (higher hemolytic concentration 50) than Kn2-5R-NH2 (l-enantiomer). Furthermore, peptide Kn2-5R with the least hydrophobicity had the lowest hemolytic activity and showed the highest specificity to Salmonella (the highest selectivity index). This study also explained the relationship of peptide physicochemical properties and bioactivities that would fulfill and accelerate progress in peptide antibiotic research and development.

Excitatory postsynaptic potentials recorded from regular-spiking cells in layers II/III of rat sensorimotor cortex

1992 ◽  
Vol 67 (3) ◽  
pp. 728-737 ◽  
Author(s):  
G. G. Hwa ◽  
M. Avoli
Keyword(s):  
Nmda Receptor Antagonist ◽  
Short Latency ◽  
Neuronal Membrane ◽  
Dependent Manner ◽  
Excitatory Postsynaptic Potentials ◽  
Normal Medium ◽  
Postsynaptic Potentials ◽  
Extracellular Stimuli ◽  
Relationship Of

1. Intracellular recording techniques were used to investigate the physiological and pharmacological properties of stimulus-induced excitatory postsynaptic potentials (EPSPs) recorded in regular-spiking cells located in layers II/III of rat sensorimotor cortical slices maintained in vitro. 2. Depending on the strength of the extracellular stimuli, a pure EPSP or an EPSP-inhibitory postsynaptic potential sequence was observed under perfusion with normal medium. The EPSPs displayed short latency of onset [2.4 +/- 0.7 (SD) ms] and were able to follow repetitive stimulation (tested less than or equal to 5 Hz). Variation of the membrane potential (Vm) revealed two types of voltage behavior for the short-latency EPSP. The first type decreased in amplitude with depolarization and increased in amplitude with hyperpolarization. In contrast, the second type behaved anomalously by increasing and decreasing in size after depolarization and hyperpolarization, respectively. 3. Several experimental procedures were carried out to investigate the mechanism underlying the anomalous voltage behavior of the EPSP. Results indicated that this type of Vm dependency could be mimicked by an intrinsic response evoked by a brief pulse of depolarizing current and could be abolished by N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (50 mM). Furthermore, the EPSP was not sensitive to the N-methyl-D-aspartate (NMDA) receptor antagonist 3-((+-)-2-carboxypiperazin-4-yl)-propyl-1-phosphonate (CPP, 10 microM). Thus the anomalous voltage relationship of the neuronal membrane. 4. The involvement of non-NMDA receptors in excitatory synaptic transmission was investigated with their selective antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX, 1-10 microM). This drug greatly reduced or completely blocked the EPSP in a dose-dependent manner (1-10 microM). The IC50 for the CNQX effect was approximately 2 microM. In the presence of CNQX (10 microM) and glycine (10 microM), synaptic stimulation failed to elicit firing of action potential. However, a CPP-sensitive EPSP was observed. 5. When synaptic inhibition was reduced by low concentration of bicuculline methiodide (BMI, 1-2 microM), extracellular stimulation revealed late EPSPs (latency to onset: 10-30 ms) that were not discernible in normal medium. Similar to the short-latency EPSP, the Vm dependency displayed by this late EPSP could be modified by inward membrane rectifications. The late EPSP appeared to be polysynaptic in origin because 1) its latency of onset was long and variable and 2) it failed to follow repetitive stimuli delivered at a frequency that did not depress the short-latency EPSP.(ABSTRACT TRUNCATED AT 400 WORDS)

Morphology-Function Relationship of Thermoelectric Nanocomposite Films from PEDOT:PSS with Silicon Nanoparticles

2017 ◽  
Vol 3 (8) ◽  
pp. 1700181 ◽  
Author(s):  
Nitin Saxena ◽  
Mihael Čorić ◽  
Anton Greppmair ◽  
Jan Wernecke ◽  
Mika Pflüger ◽  
...  
Keyword(s):  
Silicon Nanoparticles ◽  
Nanocomposite Films ◽  
Function Relationship ◽  
Relationship Of
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