Inhibition of protein aggregation: supramolecular assemblies of arginine hold the key

Das, Utpal ; Hariprasad, Gururao ; Ethayathulla, Abdul S. ; Manral, Pallavi ; Das, Taposh K. ; Pasha, Santosh ; Mann, Anita ; Ganguli, Munia ; Verma, Amit K. ; Bhat, Rajiv ; Chandrayan, Sanjeev Kumar ; Ahmed, Shubbir ; Sharma, Sujata ; Kaur, Punit ; Singh, Tej P. ; Srinivasan, Alagiri (2007) Inhibition of protein aggregation: supramolecular assemblies of arginine hold the key PLos One, 2 (11). No.PP.given. ISSN 1932-6203

PDF - Publisher Version

Official URL:

Related URL:


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 (Aβ1-42) peptide is modified. Changes in the hydrodynamic volume of Aβ1-42 in the presence of arginine measured by size exclusion chromatography show that arginine binds to Aβ1-42. Arginine increases the solubility of Aβ1-42 peptide in aqueous medium. It decreases the aggregation of Aβ1-42 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.

Item Type:Article
Source:Copyright of this article belongs to Public Library of Science.
ID Code:49111
Deposited On:18 Jul 2011 14:09
Last Modified:18 May 2016 03:57

Repository Staff Only: item control page