Location and binding mechanism of an ESIPT probe 3-hydroxy-2-naphthoic acid in unsaturated fatty acid bound serum albumins.
The binding site and the binding mechanism of 3-hydroxy-2-naphthoic acid (3HNA) in oleic acid (OA) bound serum albumins (bovine serum albumin (BSA) and human serum albumin (HSA)) have been determined using steady state and time resolved emission of tryptophan residues (Trp) in proteins and the ESIPT emission of 3HNA. Time resolved anisotropy of the probe 3HNA and low temperature phosphorescence of Trp residues of BSA in OA bound BSA at 77K reveals a drastic change of the binding site of 3HNA in the ternary system compared to that in the free protein. 3HNA binds near Trp213 in the ternary system whereas 3HNA binds near Trp134 in the free protein. The structure of OA bound BSA generated using docking methodology exhibits U-bend configuration of all bound OA. The docked pose of 3HNA in the free protein and in OA bound albumins (ternary systems) and the concomitant perturbation of the structure of proteins around the binding region of 3HNA corroborate the enhanced ESIPT emission of 3HNA and the energy transfer efficiency from the donor Trp213 of BSA to 3HNA acceptor in 3HNA-OA-BSA system.
Department of Chemistry, Presidency University, Kolkata 700073, India.
Shyamal Kr
SK
Ghorai
Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
Debi Ranjan
DR
Tripathy
Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
Swagata
S
Dasgupta
Department of Chemistry, Presidency University, Kolkata 700073, India. Electronic address: sanjibg@cal2.vsnl.net.in.
Sanjib
S
Ghosh
D001665:Binding Sites; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005454:Fluorescence Polarization; D006801:Humans; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D009284:Naphthols / Q000737:chemistry / Q000378:metabolism*; D019301:Oleic Acid / Q000737:chemistry / Q000378:metabolism*; D011487:Protein Conformation; D012709:Serum Albumin / Q000378:metabolism; D012710:Serum Albumin, Bovine / Q000737:chemistry* / Q000378:metabolism*; D014364:Tryptophan / Q000737:chemistry
D005231:Fatty Acids, Unsaturated; D009284:Naphthols; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D019301:Oleic Acid; D014364:Tryptophan; C021303:3-hydroxy-2-naphthoic acid
Accessible surface area; Anisotropy; Energy transfer; Oleic acid; Proteins; Triplet state