Influence of the methyl position on the binding of 5-epi-taiwaniaquinone G to HHb investigated by spectrofluorimetry and molecular modelling

ABSTRACT

The interactions of human haemoglobin (HHb) with 5-epi-taiwaniaquinone G (G1) and one structural analogue of 5-epi-taiwaniaquinone G (G2) systematically by UV–vis absorption spectroscopy and fluorescence spectroscopy in combination with molecular modelling are studied in this paper. They caused the fluorescence quenching of HHb by the formation of complex. The binding constants and thermodynamic parameters were obtained. The hydrophobic and electrostatic interactions were the predominant intermolecular forces to stabilise these complexes. Results of thermodynamic analysis and molecular modelling showed that G2 was the stronger quencher and bound to HHb with higher affinity. The result of molecular modelling is close to that obtained by experimental methods.

KEYWORDS:

• Human haemoglobin
• 5-epi-taiwaniaquinone G
• fluorescence
• molecular modelling

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

We are grateful to the National Natural Science Foundation of China [81330075] and 2015 Key Science and Technology Plan Project of Henan Province [152102310065] for financial support.