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Experimental and theoretical charge‐density analysis of hippuric acid: insight into its binding with human serum albumin
Author(s) -
Hasil Asma,
Mehmood Arshad,
Ahmed Maqsood
Publication year - 2019
Publication title -
acta crystallographica section b
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.604
H-Index - 33
ISSN - 2052-5206
DOI - 10.1107/s2052520619007911
Subject(s) - chemistry , hippuric acid , hydrogen bond , atoms in molecules , molecule , intermolecular force , density functional theory , dipole , human serum albumin , charge density , electron density , crystallography , binding energy , chemical polarity , computational chemistry , electron , atomic physics , organic chemistry , urine , biochemistry , physics , chromatography , quantum mechanics
In order to comprehend the binding of an important metabolite, hippuric acid, with human serum albumin and to understand its chemical and electronic nature, an experimental charge‐density analysis has been carried out using high‐resolution diffraction data collected under cryogenic conditions, and all the results have been compared with theoretical findings using the B3LYP/6‐311++g(2d,2p) level of theory. The structure displays very strong classical hydrogen bonds as well as other noncovalent interactions, which have been fully characterized using Hirshfeld surface analysis and Bader's quantum theory of atoms in molecules. Contact analysis on the Hirshfeld surfaces shows that the O…H, C…H and C…N intermolecular interactions are enriched and gives their relative strengths. Topological analysis of the electron density shows the charge concentration/depletion of hippuric acid bonds in the crystal structure. Electrostatic parameters such as atomic charges and dipole moments were calculated. The mapping of atomic basins and the calculation of respective charges show the atomic volumes of each atom as well as their charge contributions in the hippuric acid crystal structure. The dipole‐moment calculations show that the molecule is very polar in nature. Calculations of the electrostatic potential show that the chain part of the molecule has a higher concentration of negative charge than the ring, which might be instrumental in its strong binding with the polar residues of site II of human serum albumin.