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Ki Hyun Nam - One of the best experts on this subject based on the ideXlab platform.
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Triglycine-Based Approach for Identifying the Substrate Recognition Site of an Enzyme
Crystals, 2019Co-Authors: Ki Hyun NamAbstract:Various peptides or non-structural amino acids are recognized by their specific target proteins, and perform a biological role in various pathways in vivo. Understanding the interactions between target protein and peptides (or non-structural amino acids) provides key information on the molecular interactions, which can be potentially translated to the development of novel drugs. However, it is experimentally challenging to determine the crystal structure of protein–peptide complexes. To obtain structural information on the substrate recognition of the peptide-recognizing enzyme, X-ray crystallographic studies were performed using Triglycine (Gly-Gly-Gly) as the main-chain of the peptide. The crystal structure of Parengyodontium album Proteinase K in complex with triglcyine was determined at a 1.4 A resolution. Two different bound conformations of Triglycine were observed at the substrate recognition site. The Triglycine backbone forms stable interactions with β5-α4 and α5-β6 loops of the main-chain. One of the Triglycine-binding conformations was identical to the binding mode of a peptide-based inhibitor from a previously reported crystal structure of Proteinase K. Triglycine has potential application in X-ray crystallography in order to identify the substrate recognition sites in the peptide binding enzymes.
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Triglycine-Based Approach for Identifying the Substrate Recognition Site of an Enzyme
2019Co-Authors: Ki Hyun NamAbstract:Various peptides or non-structural amino acids are recognized by their specific target proteins and perform biological role in various pathways in vivo. Understanding the interactions between target protein and peptides (or non-structural amino acids) provides key information on the molecular interactions, which can be potentially translated to the development of novel drugs. However, it is experimentally challenging to determine the crystal structure of protein-peptide complexes. To obtain structural information on substrate recognition of peptide-recognizing enzyme, X-ray crystallographic studies were performed using Triglycine (Gly-Gly-Gly) as main-chain of peptide. The crystal structure of Parengyodontium album Proteinase K in complex with triglcyine was determined at 1.4 Å resolution. Two different bound conformations of Triglycine were observed at the substrate recognition site. The Triglycine backbone forms stable interactions with β5-α4 and α5-β6 loops of main-chain. One of the Triglycine-binding conformations was identical with the binding mode of a peptide-based inhibitor from a previously reported crystal structure of Proteinase K. Triglycine has potential application X-ray crystallography to identify substrate recognition sites in peptide binding enzymes.
Kun Lin Yang - One of the best experts on this subject based on the ideXlab platform.
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A Method of Obtaining High Selectivity for Copper Ions on Triglycine Decorated Surfaces
Journal of Physical Chemistry C, 2008Co-Authors: Xinyan Bi, Chee Hua Heng, Kun Lin YangAbstract:We report a method of controlling the conformations of immobilized Triglycine and improving its selectivity for copper ion by mixing equal molar of Triglycine and copper ion during the immobilization step. Our attenuated total reflectance-Fourier transformation infrared (ATR-FTIR) spectroscopy shows that, when Triglycine molecules are immobilized in the presence of copper ions, both amide I and amide II bands of Triglycine increase, which can be attributed to the conformational change of Triglycine from a random coil to a loop structure. Interestingly, even after copper ion is removed, the loop structure is still maintained, possibly due to the formation of intermolecular hydrogen bonds between adjacent Triglycine molecules. Immobilized Triglycine molecules with a loop structure show excellent complexation capability and selectivity for copper ion. Even in the presence of 100× other metal ions such as zinc and nickel, surface immobilized Triglycine with a loop structure still preferentially binds to coppe...
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A Method of Obtaining High Selectivity for Copper Ions on Triglycine Decorated Surfaces
The Journal of Physical Chemistry C, 2008Co-Authors: Chee Hua Heng, Kun Lin YangAbstract:We report a method of controlling the conformations of immobilized Triglycine and improving its selectivity for copper ion by mixing equal molar of Triglycine and copper ion during the immobilizati...
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preparation of ion imprinted silica gels functionalized with glycine diglycine and Triglycine and their adsorption properties for copper ions
Langmuir, 2007Co-Authors: Rong Jia Lau, Kun Lin YangAbstract:We report a new procedure for modifying the surface of silica gels with glycine, diglycine, and Triglycine in the presence of copper ions to create a new type of copper-imprinted sorbent, which exhibits a high adsorption capacity and selectivity for copper ions. Our results show that copper adsorbed onto the copper-imprinted silica gel is 50% higher than that on nonimprinted silica gel at pH 4.5. The high adsorption capacity observed for the copper-imprinted silica gel is attributed to the stable copper complexes formed with two adjacent glycine, diglycine, or Triglycine molecules with proper intermolecular distances obtained from the ion-imprinting procedure. Another possible reason for the high adsorption capacity is that the ion-imprinting procedure prevents the surface from being overcrowded; therefore, copper ions can form very stable 1:1 complexes with immobilized diglycine or Triglycine. Interestingly, the imprinting effect is even more pronounced when the adsorption experiments are conducted in th...
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Preparation of Ion-Imprinted Silica Gels Functionalized with Glycine, Diglycine, and Triglycine and Their Adsorption Properties for Copper Ions
Langmuir : the ACS journal of surfaces and colloids, 2007Co-Authors: Rong Jia Lau, Kun Lin YangAbstract:We report a new procedure for modifying the surface of silica gels with glycine, diglycine, and Triglycine in the presence of copper ions to create a new type of copper-imprinted sorbent, which exhibits a high adsorption capacity and selectivity for copper ions. Our results show that copper adsorbed onto the copper-imprinted silica gel is 50% higher than that on nonimprinted silica gel at pH 4.5. The high adsorption capacity observed for the copper-imprinted silica gel is attributed to the stable copper complexes formed with two adjacent glycine, diglycine, or Triglycine molecules with proper intermolecular distances obtained from the ion-imprinting procedure. Another possible reason for the high adsorption capacity is that the ion-imprinting procedure prevents the surface from being overcrowded; therefore, copper ions can form very stable 1:1 complexes with immobilized diglycine or Triglycine. Interestingly, the imprinting effect is even more pronounced when the adsorption experiments are conducted in the presence of competing metal ions such as magnesium and calcium. The copper-imprinted silica gel exhibits a higher adsorption capacity than does the nonimprinted silica gel for all pH values, even when the concentrations of magnesium and calcium are 50 and 76 times higher than the concentration of copper.
P. Ramasamy - One of the best experts on this subject based on the ideXlab platform.
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Electrical characterization on l-tyrosine doped Triglycine sulfate single crystals
Materials Research Bulletin, 2002Co-Authors: G. Arunmozhi, E. De Matos Gomes, K Meera, P. RamasamyAbstract:Abstract Dielectric, hysteresis, and scanning electron microscope studies on l -tyrosine doped Triglycine sulfate (TyTGS) are reported. Increase in the relative permittivity compared to Triglycine sulfate is observed on the doped crystal. Low frequency dielectric relaxation process is found to be modified in TyTGS crystals. No significant change in the spontaneous polarization compared to pure Triglycine sulfate is observed. Increase in the coercive field in TyTGS compared to pure Triglycine sulfate suggests that the dopant hinders the domain wall motion. Lens shaped domains, typical of Triglycine sulfate are also observed on TyTGS crystal.
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effect of rare earth dopants on the growth and properties of Triglycine sulphate single crystals
Journal of Crystal Growth, 2002Co-Authors: R Muralidharan, R Mohankumar, P M Ushasree, R Jayavel, P. RamasamyAbstract:Abstract The effect of rare-earth ion dopants La, Ce and Nd on the growth aspects and ferroelectric properties of Triglycine sulphate single crystals is reported. The incorporation of dopants into the grown crystals is far below the concentration in the mother solution. The dopants significantly modify the morphology of the crystals. Dielectric measurements revealed that the dielectric constant of Ce doped Triglycine sulphate (TGS) increases rapidly at the transition temperature. Well-saturated rectangular hysteresis loops have been observed for all the doped crystals. Lenticular ferroelectric domain patterns were observed on the [0 1 0] plane of the grown crystals. Among the three dopants, La doped TGS possess a high Curie temperature and coercive field values.
V. A. Sharnin - One of the best experts on this subject based on the ideXlab platform.
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thermodynamics of the complex formation between cu 2 and Triglycine in water ethanol solutions at 298 k
Russian Journal of Physical Chemistry A, 2017Co-Authors: Pham L Thi, T. R. Usacheva, T. M. Khrenova, V. A. SharninAbstract:Thermodynamic functions Δr H, Δr G, and TΔr S of the complex formation between Cu2+ and Triglycine in water–ethanol solutions are calculated on the basis of calorimetric data. It is found that raising the concentration of EtOH results in a monotonic increase in the exothermic effect of [CuHL]2+ complex formation due to the weakening of Triglycine solvation with the mutual compensation of ion solvation contributions. The enthalpy of [CuL]+ complex formation has an exothermic maximum at 0.1−0.3 molar fractions of EtOH due to competition between the solvation contributions from ions and ligands.
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Constants and thermodynamics of the acid-base equilibria of Triglycine in water–ethanol solutions containing sodium perchlorate at 298 K
Russian Journal of Physical Chemistry A, 2016Co-Authors: L. Pham Tkhi, T. R. Usacheva, N. V. Tukumova, N. E. Koryshev, T. M. Khrenova, V. A. SharninAbstract:The acid−base equilibrium constants for glycyl-glycyl-glycine (Triglycine) in water–ethanol solvents containing 0.0, 0.1, 0.3, and 0.5 mole fractions of ethanol are determined by potentiometric titration at 298.15 K and an ionic strength of 0.1, maintained with sodium perchlorate. It is established that an increase in the ethanol content in the solvent reduces the dissociation constant of the carboxyl group of Triglycine (increases pK1) and increases the dissociation constant of the amino group of Triglycine (decreases pK2). It is noted that the weakening of the acidic properties of a triglycinium ion upon an increase of the ethanol content in the solvent is due to the attenuation of the solvation shell of the zwitterionic form of Triglycine, and to the increased solvation of triglycinium ions. It is concluded that the acid strength of Triglycine increases along with a rise in the EtOH content in the solvent, due to the desolvation of the tripeptide zwitterion and the enhanced solvation of protons.
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constants and thermodynamics of the acid base equilibria of Triglycine in water ethanol solutions containing sodium perchlorate at 298 k
Russian Journal of Physical Chemistry A, 2016Co-Authors: Pham L Tkhi, T. R. Usacheva, N. V. Tukumova, N. E. Koryshev, T. M. Khrenova, V. A. SharninAbstract:The acid−base equilibrium constants for glycyl-glycyl-glycine (Triglycine) in water–ethanol solvents containing 0.0, 0.1, 0.3, and 0.5 mole fractions of ethanol are determined by potentiometric titration at 298.15 K and an ionic strength of 0.1, maintained with sodium perchlorate. It is established that an increase in the ethanol content in the solvent reduces the dissociation constant of the carboxyl group of Triglycine (increases pK1) and increases the dissociation constant of the amino group of Triglycine (decreases pK2). It is noted that the weakening of the acidic properties of a triglycinium ion upon an increase of the ethanol content in the solvent is due to the attenuation of the solvation shell of the zwitterionic form of Triglycine, and to the increased solvation of triglycinium ions. It is concluded that the acid strength of Triglycine increases along with a rise in the EtOH content in the solvent, due to the desolvation of the tripeptide zwitterion and the enhanced solvation of protons.
T. Iglesias - One of the best experts on this subject based on the ideXlab platform.
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Journal of the Korean Physical Society, Vol. 32, Feburary 1998, pp. S28∼S30 Metastable Behavior in Uniaxial Ferroelectrics TGS and TGSe near TC
2016Co-Authors: J. Fernández R. Del Castillo, J. Przeslawski, T. Iglesias, B. Noheda, J. A. GonzaloAbstract:High resolution hysteresis loops measurements in Triglycine sulfate (ordinary critical point) and in Triglycine selenate (tricritical point) allow the approximate characterization of the behavior in the metastable region (E < 0, P> 0, or vice versa) at T ≤ TC. The coercive field may be assumed to reflect three different regimes corresponding with three switching regimes. The observed coerciv
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Scaling Equation of State for Ferroelectric Triglycine Selenate at T ≈ Tc
Europhysics Letters (EPL), 1994Co-Authors: T. Iglesias, Beatriz Noheda, Blanca Gallego, J.r. Fernández Del Castillo, Ginés Lifante, Julio A. GonzaloAbstract:Digital data of polarization vs. field on Triglycine selenate at closely spaced temperature intervals (ΔT ≈ 0.015) in the vicinity of the quasi-tricritical point of Triglycine selenate have been collected. These data fulfill very well the scaling equation of state e = + (1/5)5 (where e− and e+ correspond to T Tc, respectively) where = (Ps/Pso)/{1 − T/Tc}1/4 and e = (E/Eso)/{1 − T/Tc}5/4 are the scaling variables, with tricritical exponents β = 1/4, δ = 5.
