title: Characterization of the binding of an anticancer drug, lapatinib to human serum albumin.
abstract: Interaction of a promising anticancer drug, lapatinib (LAP) with the major transport protein in human blood circulation, human serum albumin (HSA) was investigated using fluorescence and circular dichroism (CD) spectroscopy as well as molecular docking analysis. LAP-HSA complex formation was evident from the involvement of static quenching mechanism, as revealed by the fluorescence quenching data analysis. The binding constant, Ka value in the range of 1.49-1.01×10(5)M(-1), obtained at three different temperatures was suggestive of the intermediate binding affinity between LAP and HSA. Thermodynamic analysis of the binding data (∆H=-9.75kJmol(-1) and ∆S=+65.21Jmol(-1)K(-1)) suggested involvement of both hydrophobic interactions and hydrogen bonding in LAP-HSA interaction, which were in line with the molecular docking results. LAP binding to HSA led to the secondary and the tertiary structural alterations in the protein as evident from the far-UV and the near-UV CD spectral analysis, respectively. Microenvironmental perturbation around Trp and Tyr residues in HSA upon LAP binding was confirmed from the three-dimensional fluorescence spectral results. LAP binding to HSA improved the thermal stability of the protein. LAP was found to bind preferentially to the site III in subdomain IB on HSA, as probed by the competitive drug displacement results and supported by the molecular docking results. The effect of metal ions on the binding constant between LAP and HSA was also investigated and the results showed a decrease in the binding constant in the presence of these metal ions.
authors.affiliation: Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Md Zahirul
authors.initials: MZ
authors.lastname: Kabir
authors.affiliation: Bioinformatics Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Abdul Kadir
authors.initials: AK
authors.lastname: Mukarram
authors.affiliation: Bioinformatics Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia; Centre of Research for Computational Sciences and Informatics for Biology, Bioindustry, Environment, Agriculture and Healthcare, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Saharuddin B
authors.initials: SB
authors.lastname: Mohamad
authors.affiliation: Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Zazali
authors.initials: Z
authors.lastname: Alias
authors.affiliation: Biomolecular Research Group, Biochemistry Programme, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia; Centre of Research for Computational Sciences and Informatics for Biology, Bioindustry, Environment, Agriculture and Healthcare, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia. Electronic address: saadtayyab2004@yahoo.com.
authors.forename: Saad
authors.initials: S
authors.lastname: Tayyab
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000378:metabolism*; D001665:Binding Sites; D002942:Circular Dichroism; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D000077341:Lapatinib; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D062105:Molecular Docking Simulation; D011485:Protein Binding; D055550:Protein Stability; D017434:Protein Structure, Tertiary; D011799:Quinazolines / Q000737:chemistry / Q000378:metabolism*; D012709:Serum Albumin / Q000737:chemistry / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics
chemical_list: D000970:Antineoplastic Agents; D008670:Metals; D011799:Quinazolines; D012709:Serum Albumin; D000077341:Lapatinib
keywords: Drug–protein interaction; Fluorescence quenching; Human serum albumin; Lapatinib; Molecular docking