title: An investigation of folic acid-protein association sites and the effect of this association on folic acid self-assembly.
abstract: The contribution of folic acid (FA)-tryptophan interactions to FA-protein association was investigated in the context of using FA as a drug carrier in protein delivery systems. Bovine serum albumin (BSA) and indolicidin were used as model proteins in the study. The FA-BSA complex was characterized by using the Bradford reagent to identify the impact of FA-BSA association on BSA-dye reagent interactions. UV-visible spectroscopic analysis of the FA-BSA mixture showed that the absorbance maximum of BSA-dye reagent occurred at 595 nm, even after the association of FA with BSA. This confirms that protonated amino acid groups of the protein are not involved in FA-BSA association. Moreover, molecular dynamics (MD) simulation confirmed the presence of an associative interaction between aromatic moieties in FA and tryptophan moieties in the indolicidin molecule, which disrupted FA self-assembly. An X-ray diffraction (XRD) study showed that there was limited disruption of FA self-assembly after the addition of BSA or tryptophan. This suggests that FA and BSA are compatible and associate with each other. Graphical Abstract Mechanism of folic acid and protein association.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 110016.
authors.forename: Rajat
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 110016.
authors.forename: Prasanta
authors.initials: P
authors.lastname: Kalita
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 110016.
authors.forename: Omkar
authors.initials: O
authors.lastname: Patil
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Delhi, New Delhi, India, 110016. sanat.mohanty@gmail.com.
authors.forename: Sanat
authors.initials: S
authors.lastname: Mohanty
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000378:metabolism; D004337:Drug Carriers; D005492:Folic Acid / Q000378:metabolism*; D056004:Molecular Dynamics Simulation; D011485:Protein Binding; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013057:Spectrum Analysis; D014364:Tryptophan / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D023181:Antimicrobial Cationic Peptides; D004337:Drug Carriers; C073143:indolicidin; D012710:Serum Albumin, Bovine; D014364:Tryptophan; D005492:Folic Acid
keywords: Folate; Indolicidin; Molecular dynamics; Spectroscopy; Tryptophan