73 research outputs found
Inhibition of Protein Aggregation: Supramolecular Assemblies of Arginine Hold the Key
BACKGROUND: Aggregation of unfolded proteins occurs mainly through the exposed hydrophobic surfaces. Any mechanism of inhibition of this aggregation should explain the prevention of these hydrophobic interactions. Though arginine is prevalently used as an aggregation suppressor, its mechanism of action is not clearly understood. We propose a mechanism based on the hydrophobic interactions of arginine. METHODOLOGY: We have analyzed arginine solution for its hydrotropic effect by pyrene solubility and the presence of hydrophobic environment by 1-anilino-8-naphthalene sulfonic acid fluorescence. Mass spectroscopic analyses show that arginine forms molecular clusters in the gas phase and the cluster composition is dependent on the solution conditions. Light scattering studies indicate that arginine exists as clusters in solution. In the presence of arginine, the reverse phase chromatographic elution profile of Alzheimer's amyloid beta 1-42 (Abeta(1-42)) peptide is modified. Changes in the hydrodynamic volume of Abeta(1-42) in the presence of arginine measured by size exclusion chromatography show that arginine binds to Abeta(1-42). Arginine increases the solubility of Abeta(1-42) peptide in aqueous medium. It decreases the aggregation of Abeta(1-42) as observed by atomic force microscopy. CONCLUSIONS: Based on our experimental results we propose that molecular clusters of arginine in aqueous solutions display a hydrophobic surface by the alignment of its three methylene groups. The hydrophobic surfaces present on the proteins interact with the hydrophobic surface presented by the arginine clusters. The masking of hydrophobic surface inhibits protein-protein aggregation. This mechanism is also responsible for the hydrotropic effect of arginine on various compounds. It is also explained why other amino acids fail to inhibit the protein aggregation
Recommended from our members
Condition comprehension predicts compliance for adolescents under probation supervision
Noncompliance is a chronic problem among youth court ordered to probation supervision, often placing them in jeopardy of deeper involvement with the juvenile justice system. Legal comprehension theory and goal setting theory suggests that youth understanding of their probation requirements may predict compliance. This study explored the effect of condition comprehension on short-term compliance with probation requirements in a sample of probation youths (n = 101). Results of the multilevel logistic regression analysis demonstrated that youth with a detailed understanding of their conditions were more likely to comply with probation requirements, but that this effect was moderated by age and by emotion regulation. Understanding was not related to compliance for youth younger than 14 and for youth who scored low on a measure of emotion regulation. Results of this study provide support for efforts by probation departments to foster youth comprehension of their conditions, and reveal the need to establish probation strategies suited to younger youth and youth with poor emotion regulation
Recommended from our members
Experimental Determination of Anomalous Scattering Lengths of Samarium for Thermal Neutrons
Anomalous scattering lengths of natural Sm for thermal neutrons with wavelengths between 0.827 and 1.300 A have been determined using a single crysrtal of a Sm-complex of known structure. 140 selected reflections were measured at each wavelength and b/sub 0/ + b' and b'' refined in each case. The values obtained are in good agreement with theoretical values obtained from a Breit-Wigner calculation using tabulated resonance parameters for /sup 149/Sm. A value of b/sub 0/ = 4.3 +- 0.2 fm is deduced from the diffraction experiment
Theoretical predictions and single-crystal neutron diffraction and inelastic neutron scattering studies on the reaction of dihydrogen with the dinuclear dinitrogen complex of zirconium [P2N2]Zr(mu-eta(2)-N-2)Zr[P2N2], P2N2=PhP(CH2SiMe2NSiMe2CH2)(2)PPh
A single-crystal neutron diffraction analysis along with density functional calculations and incoherent inelastic neutron scattering studies has conclusively shown that the dihydrogen adduct of [P2N2]Zr(mu-eta(2)-N-2)Zr[P2N2] (1) (where P2N2 = PhP(CH2SiMe2NSiMe2CH2)(2)PPh) is [P2N2]Zr(mu-eta(2)-N2H)(mu-H)Zr[P2N2] (2), the complex with a bridging hydride and a N-N-H moiety, and not the dihydrogen complex [P2N2]Zr(mu-eta(2)-N-2)(mu-eta(2)-H-2)Zr[P2N2] (3), as was proposed on the basis of X-ray crystallographic data. In addition, DFT calculations show that the reaction of 1 with both H-2 and SiH4 is exothermic while an endothermic reaction is found for the reaction of 1 with CH4
- …