Fluorescence resonance energy transfer from tryptophan in human serum albumin to a bioactive indoloquinolizine system

Journal of Chemical Sciences

Arabinda Mallick¹  Basudeb Haldar¹  Alok Chakrabarty¹  Nitin Chattopadhyay1¹  Paramita Das¹ 

[1] Department of Chemistry, Jadavpur University, Kolkata 700 032 $$

关键词: Fluorescence resonance energy transfer;    photosensitisation;    human serum albumin;    fluorescence quenching;    overlap integral;    Stern-Volmer constant.;   

DOI  :  

来源: Indian Academy of Sciences

【 摘 要 】

The interaction between a bioactive molecule, 3-acetyl-4-oxo-6,7-dihydro-12H indolo-[2,3-a] quinolizine (AODIQ), with human serum albumin (HSA) has been studied using steady-state absorption and fluorescence techniques. A 1 : 1 complex formation has been established and the binding constant (𝐾) and free energy change for the process have been reported. The AODIQ-HSA complex results in fluorescence resonance energy transfer (FRET) from the tryptophan moiety of HSA to the probe. The critical energy-transfer distance (𝑅0) for FRET and the Stern-Volmer constant (𝐾sv) for the fluorescence quenching of the donor in the presence of the acceptor have been determined. Importantly, 𝐾SV has been shown to be equal to the binding constant itself, implying that the fluorescence quenching arises only from the FRET process. The study suggests that the donor and the acceptor are bound to the same protein at different locations but within the quenching distance.

【 授权许可】

Unknown