The binding affinity of amino acid–protein: hydroxyproline binding site I on human serum albumin

2012 ◽  
Vol 10 (41) ◽  
pp. 8314 ◽  
Author(s):  
Ximin Zhou ◽  
Wenjuan Lü ◽  
Li Su ◽  
Yalei Dong ◽  
Qianfeng Li ◽  
...  
Keyword(s):  
Amino Acid ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Binding Site ◽  
Binding Affinity ◽  
Acid Protein ◽  
Amino Acid Protein

scholarly journals Oxidative Alteration of Trp-214 and Lys-199 in Human Serum Albumin Increases Binding Affinity with Phenylbutazone: A Combined Experimental and Computational Investigation

2018 ◽  
Vol 19 (10) ◽  
pp. 2868 ◽  
Author(s):  
Luiza Bertozo ◽  
Ernesto Tavares Neto ◽  
Leandro Oliveira ◽  
Valdecir Ximenes
Keyword(s):  
Amino Acid ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Interaction Energy ◽  
Score Function ◽  
Oxidation Products ◽  
Amino Acid Residues ◽  
Computational Investigation ◽  
A Current

Human serum albumin (HSA) is a target for reactive oxygen species (ROS), and alterations of its physiological functions caused by oxidation is a current issue. In this work, the amino-acid residues Trp-214 and Lys-199, which are located at site I of HSA, were experimentally and computationally oxidized, and the effect on the binding constant with phenylbutazone was measured. HSA was submitted to two mild oxidizing reagents, taurine monochloramine (Tau-NHCl) and taurine dibromamine (Tau-NBr2). The oxidation of Trp-214 provoked spectroscopic alterations in the protein which were consistent with the formation of N′-formylkynurenine. It was found that the oxidation of HSA by Tau-NBr2, but not by Tau-NHCl, provoked a significant increase in the association constant with phenylbutazone. The alterations of Trp-214 and Lys-199 were modeled and simulated by changing these residues using the putative oxidation products. Based on the Amber score function, the interaction energy was measured, and it showed that, while native HSA presented an interaction energy of −21.3 kJ/mol, HSA with Trp-214 altered to N′-formylkynurenine resulted in an energy of −28.4 kJ/mol, and HSA with Lys-199 altered to its carbonylated form resulted in an energy of −33.9 kJ/mol. In summary, these experimental and theoretical findings show that oxidative alterations of amino-acid residues at site I of HSA affect its binding efficacy.

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