title: Binding and stabilization of transthyretin by curcumin.
abstract: Biophysical evidences suggest that transthyretin (TTR) tetramer dissociation to the monomeric intermediate and subsequent polymerization leads to amyloid fibril formation, which is implicated in the pathogenesis of familial amyloid polyneuropathy (FAP) and senile systemic amyloidosis (SSA). Hence, inhibition of fibril formation is considered a potential therapeutic strategy. Here in we demonstrate that curcumin, a phenolic constituent of curry spice turmeric, binds to the active site of TTR through fluorescence quenching and ANS displacement studies. Binding of curcumin appears to inhibit the denaturant induced tertiary and quaternary structural changes in TTR as monitored by intrinsic emission fluorescence and glutaraldehyde cross-linking studies. However, curcumin did not bind to TTR at acidic pH. Protonation/ isomerization of the side chain oxygen atoms of curcumin at low pH might hamper the binding. These results suggest that curcumin binds to and stabilizes TTR thereby highlight the importance of the side chain conformations of the ligand in binding to TTR.
authors.affiliation: National Institute of Nutrition, Jamai Osmania, Tarnaka, Hyderabad 500604, India.
authors.forename: Raghu
authors.initials: R
authors.lastname: Pullakhandam
authors.forename: P N B S
authors.initials: PN
authors.lastname: Srinivas
authors.forename: Madhavan K
authors.initials: MK
authors.lastname: Nair
authors.forename: G Bhanuprakash
authors.initials: GB
authors.lastname: Reddy
mesh_terms: D020134:Catalytic Domain; D003474:Curcumin / Q000494:pharmacology*; D011228:Prealbumin / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D011228:Prealbumin; D003474:Curcumin