Curcumin and kaempferol prevent lysozyme fibril formation by modulating aggregation kinetic parameters.
Interaction of small molecule inhibitors with protein aggregates has been studied extensively, but how these inhibitors modulate aggregation kinetic parameters is little understood. In this work, we investigated the ability of two potential aggregation inhibiting drugs, curcumin and kaempferol, to control the kinetic parameters of aggregation reaction. Using thioflavin T fluorescence and static light scattering, the kinetic parameters such as amplitude, elongation rate constant and lag time of guanidine hydrochloride-induced aggregation reactions of hen egg white lysozyme were studied. We observed a contrasting effect of inhibitors on the kinetic parameters when aggregation reactions were measured by these two probes. The interactions of these inhibitors with hen egg white lysozyme were investigated using fluorescence quench titration method and molecular dynamics simulations coupled with binding free energy calculations. We conclude that both the inhibitors prolong nucleation of amyloid aggregation through binding to region of the protein which is known to form the core of the protein fibril, but once the nucleus is formed the rate of elongation is not affected by the inhibitors. This work would provide insight into the mechanism of aggregation inhibition by these potential drug molecules.
Department of Chemistry, UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India.
Mohanish S
MS
Borana
Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India.
Pushpa
P
Mishra
Molecular Simulations Group, Department of Pharmaceutical Chemistry, Bombay College of Pharmacy, Santacruz (East), Mumbai 400098, India.
Raghuvir R S
RR
Pissurlenkar
Department of Chemistry, UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India; Department of Chemical Sciences, Tata Institute of Fundamental Research, Mumbai, India. Electronic address: hosur@tifr.res.in.
Ramakrishna V
RV
Hosur
Department of Chemistry, UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Vidhyanagari Campus, Mumbai 400098, India. Electronic address: basir.ahmad@cbs.ac.in.
Basir
B
Ahmad
D002942:Circular Dichroism; D003474:Curcumin / Q000494:pharmacology*; D005453:Fluorescence; D019791:Guanidine / Q000737:chemistry; D044949:Kaempferols / Q000494:pharmacology*; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D056004:Molecular Dynamics Simulation; D009113:Muramidase / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet
D044949:Kaempferols; C006552:kaempferol; D009113:Muramidase; D003474:Curcumin; D019791:Guanidine
Aggregation inhibitor; Aggregation kinetics; Electron microscopy; Molecular dynamics simulation; Protein misfolding; Thioflavin T assay