Structural Stability as a Probe for Molecular Evolution of Homologous Albumins Studied by Spectroscopy and Bioinformatics

Abstract

Equilibrium unfolding by guanidinium hydrochloride (GuHCl) and urea as well as evolutionary trends of two homologous albumins, pig serum albumin (PSA) and rabbit serum albumin (RSA), has been studied with circular dichroism, tryptophanyl fluorescence and bioinformatics. GuHCl cannot distinguish the contribution of electrostatic interactions to the proteins which were otherwise effectively monitored by urea. Higher differences in free energy changes due to urea than GuHCl show electrostatic interactions among charged amino acids are possibly responsible for higher structural stability of RSA in comparison to PSA. From the sequence of HSA and RSA, deletion of arginine at position 117 and the presence of one extra tryptophan at position 135 may possess some clue for lesser stability of PSA. Here, for comparison, chemical unfolding data of HSA and BSA had been taken into consideration. We found that thermodynamically RSA and PSA are closer to HSA and BSA, respectively, in accordance with their sequence homologies. Taxonomically, rabbit belongs to lagomorph which is closer to hominids than ungulates. Hence, on the basis of these thermodynamic data of protein denaturation of different species we can use this new approach to analyze the phylogenetic relationship among the major clades of eutherian mammals to obtain their evolutionary trends.

Investigation of the Interaction of Naringin Palmitate with Bovine Serum Albumin: Spectroscopic Analysis and Molecular Docking

“…The interaction forces between quencher and biomolecules may include hydrophobic force, electrostatic interactions, van der Waals interactions, hydrogen bonds, and others [15]. A different sign and magnitude for the thermodynamic parameters appeared with different interaction forces [32]–[33], such as typical hydrophobic interactions of both positive Δ H and Δ S , van der Waals force and hydrogen bonding formation showing with negative Δ H and Δ S in low dielectric media, and electrostatic interactions playing a role in negative Δ H [53].…”

“…Interaction forces between quencher and biomolecules may include hydrophobic force, electrostatic interactions, van der Waals interactions, hydrogen bonds, and others [15]. In order to map the interaction of naringin/naringin palmitate with BSA, the thermodynamic parameters were calculated using the Van’t Hoff equation [32]–[33]:where K is the binding constant to a site, R is the universal gas constant (8.314 J·mol −1 ·K −1 ), Δ H and Δ S are the changes in enthalpy and entropy during quenching process.…”

“…BSA is composed of a single-chain 583 amino acid globular nonglycoprotrein that is cross-linked with 17 cystine residues (8 disulfide bonds and 1 free thiol) [15] and has been categorized into the following three homologous domains (I, II, III): I (residues 1–195), II (196–383), and III (384–583), which are divided into nine loops (L1–L9) by 17 disulfide bonds [16]. The loops in each domain consist of a sequence of large-small-large loops that form a triplet.…”

Investigation of the interaction of anthraquinones of Cassia occidentalis seeds with bovine serum albumin by molecular docking and spectroscopic analysis: Correlation to their in vitro cytotoxic potential

“…These cross-linked residues include 8 disulfide bonds as well as 1 free thiol group (Ahmad et al, 2011). The complete structure has been known to have 3 homologous domains: I, II and III.…”

Quantification of Anti-Aggregation Activity of Chaperones: A Test-System Based on Dithiothreitol-Induced Aggregation of Bovine Serum Albumin

“…Polypeptide chain of BSA consists of 583 amino acid residues [53]. The three-dimensional structure of BSA is composed of three homologous domains (I, II, III), each formed by six helices [54].…”