Exploring the interaction forces involved in the binding of the multiple myeloma drug lenalidomide to bovine serum albumin

The binding characteristics of lenalidomide (LND) and bovine serum albumin (BSA) have been explored using spectroscopic techniques and molecular docking methods. Such interaction was shown to result in a static binding with a binding constant of 104 Lmol− 1 in a single binding site for LND on the BSA at the investigated temperatures. The thermodynamic characterization of the LND-BSA system revealed a spontaneous interaction with a ΔH° of − 4.73 ± 1.3 kJ mol− 1 and ΔS° of 67.88 ± 4.40 J mol− 1 K− 1 indicating the possible involvement of various binding forces in the LND-BSA binding. Competitive binding of LND to BSA using previously reported site markers showed that LND was bound to BSA within subdomain IIA (site I). Further confirmation was achieved through molecular docking studies of the LND-BSA binding, which established the binding site of LND with the most stable configuration of LND within the BSA. This LND conformer was shown to be situated within the active site residues Arg194, Leu197, Arg198, Ser201, Ala209, Trp213, Arg217, Val342, Ser343, Leu346, Ser453, Leu454, Asp450, Leu480, Val481, mainly forming three hydrogen bonds with Ser343, Trp.213 and Arg194 within a radius of 3.28 Å. Hence, the consistent results obtained in the current study suggested that hydrogen bonding and electrostatic forces dictate the binding of LND to BSA.