Structural basis of non-steroidal anti-inflammatory drug diclofenac binding to human serum albumin

Chem Biol Drug Des. 2015 Nov;86(5):1178-84. doi: 10.1111/cbdd.12583. Epub 2015 May 28.


Human serum albumin (HSA) is the most abundant protein in plasma, which plays a central role in drug pharmacokinetics because most compounds bound to HSA in blood circulation. To understand binding characterization of non-steroidal anti-inflammatory drugs to HSA, we resolved the structure of diclofenac and HSA complex by X-ray crystallography. HSA-palmitic acid-diclofenac structure reveals two distinct binding sites for three diclofenac in HSA. One diclofenac is located at the IB subdomain, and its carboxylate group projects toward polar environment, forming hydrogen bond with one water molecule. The other two diclofenac molecules cobind in big hydrophobic cavity of the IIA subdomain without interactive association. Among them, one binds in main chamber of big hydrophobic cavity, and its carboxylate group forms hydrogen bonds with Lys199 and Arg218, as well as one water molecule, whereas another diclofenac binds in side chamber, its carboxylate group projects out cavity, forming hydrogen bond with Ser480.

Keywords: X-ray crystallography; human serum albumin; non-steroidal anti-inflammatory drug; protein-drug interaction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents, Non-Steroidal / chemistry
  • Anti-Inflammatory Agents, Non-Steroidal / metabolism*
  • Binding Sites
  • Crystallography, X-Ray
  • Diclofenac / chemistry
  • Diclofenac / metabolism*
  • Humans
  • Molecular Docking Simulation
  • Protein Binding
  • Serum Albumin / chemistry
  • Serum Albumin / metabolism*


  • Anti-Inflammatory Agents, Non-Steroidal
  • Serum Albumin
  • Diclofenac