Abstract
•Heparin caused complete inhibition of CTAB-induced aggregation of protein.•Heparin prevents the CTAB-induced structural perturbation of the protein.•ITC measurements showed CTAB binds with the protein, however, CTAB-heparin complex suggested no specific binding.•Formation of CTAB-heparin complex was observed to inhibit the aggregation.
Heparin, a member of the glycosaminoglycan (GAG) family, is an extremely acidic sulfur-containing polysaccharide which has been suggested to be coupled with protein aggregation-related diseases including Alzheimer's, Parkinson's and Prion diseases. Here, we study the effect of heparin on the cetyltrimethylammonium bromide (CTAB)-induced aggregation of bovine serum albumin (BSA) exploiting biophysical approaches. Kinetic measurements indicated that heparin caused complete inhibition of CTAB-induced aggregation of protein with a significant decrease in the apparent rate constant. Far- and near-UV CD measurements depicted that CTAB behaves as a protein-aggregating agent. However, the perturbation of secondary and tertiary structure-induced by CTAB and the CTAB-induced amyloid formation of protein were prevented by heparin. ITC measurements revealed that enhancement of aggregation induced by CTAB was as a result of sequential binding in which CTAB binds with the protein and accompanied by exothermic heat of interaction. ITC measurements also showed that CTAB and heparin form complex while the complex does not bind with protein. Thus, we hypothesize that CTAB-Heparin complex is engaged in the inhibition of protein aggregation. Therefore, the mechanism of action of CTAB-heparin complex in inhibition of protein aggregation may be used as a basis of the development of therapeutic strategies of various neurodegenerative complications.
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