Studies of the Interaction between BSA and a Plumeran Indole Alkaloid Isolated from the Stem Bark of Aspidosperma cylindrocarpon (Apocynaceae)

Otávio Chaves, Flávia Teixeira, Heloisa Guimarães, Raimundo Braz‑Filho, Ivo José Vieira, Carlos Mauricio Sant'Anna, José Carlos Netto-Ferreira, Dari Cesarin-Sobrinho, Aurélio Ferreira
2016 Journal of the Brazilian Chemical Society  
Binding between bovine serum albumin (BSA) and a plumeran indole alkaloid (PIA) isolated from the stem bark of Aspidosperma cylindrocarpon (Apocynaceae) was studied by spectroscopic techniques (UV-Vis absorption, circular dichroism, steady state and time-resolved fluorescence), combined with molecular docking. Steady state and time resolved fluorescence data revealed that PIA can quench the BSA fluorescence via a static mechanism: energy transfer from BSA to PIA occurs with high probability.
more » ... igh probability. The binding is strong (K b ca. 10 5 -10 6 L mol -1 ), spontaneous (ΔG° ca. -35.7 kJ mol -1 at 310 K) and entropy-driven (ΔS° = 0.146 kJ mol -1 K -1 ). There is just one main binding site (n ca. 1) for the BSA:PIA interaction and the α-helix content of the albumin does not suffer significant perturbation upon PIA binding. Molecular docking results suggest site I as the main binding site to PIA, which is able to interact with the Trp-212, Arg-217, Val-342 and Pro-446 residues.
doi:10.21577/0103-5053.20160285 fatcat:cgspv2baknabhdvifllcoouoee