Binding and Fluorescence Resonance Energy Transfer (FRET) Of

Binding and fluorescence resonance energy transfer (FRET) of ruthenium(II)-bipyridine-calixarene system with proteins – Experimental and docking studies

P. Muthu Mareeswaran, D. Maheshwaran, E. Babu, S. Rajagopal*

School of Chemistry, Madurai Kamaraj University, Madurai – 625021, India

Supporting Information

Fig S1. HR-MS spectrum of Rubc2.

Fig S2. HR-MS spectrum of Rubc3.

Fig S3. UV-visible spectra of (a) Rubc2 and (b) Rubc3 (1 × 10-5 M) at various concentration of BSA (1 × 10-6 M to 9 × 10-6 M).

Fig S4. UV-visible spectra of (a) Rubc2 and (b) Rubc3 (1 × 10-5 M) with Ovalbumin at increasing concentrations (1 × 10-6 M to 9 × 10-6 M).

Fig S5. Luminescence enhancement of (a) Rubc2 and (b) Rubc3 (1 × 10-5 M) on addition of increasing concentration of OVA (1 × 10-6 M - 9 × 10-6).

Fig S6. Scatchard plot of BSA with (a) Rubc2 and (b) Rubc3.

Fig S7. Scatchard plot of Ovalbumin with (a) Rubc2 and (b) Rubc3.

Fig S8. Hills plot of BSA with (a) Rubc2 and (b) Rubc3.

Fig S9. Hills plot of Ovalbumin with (a) Rubc2 and (b) Rubc3.

Fig S10. Luminescence quenching of ovalbumin (1 × 10-5 M) in the presence of increasing concentration of (a) Rubc2 and (b) Rubc3 (1 × 10-5 - 9 × 10-5 M).

Fig S11. Stern-Volmer plot for the quenching of BSA with (a) Rubc2 and (b) Rubc3.

Fig S12. Stern-Volmer plot for the quenching of Ovalbumin with (a) Rubc2 and (b) Rubc3.

Fig S13. Luminescence decays of (a) Rubc2 and (b) Rubc3 in the absence (■) and in the presence of BSA 1 × 10-5 M (●) and 3 × 10-5 M (▲).

Fig S14. CD Sepctra of ovalbumin (9.8 × 10-7 M) in the absence (1) and in the presence of (a) Rubc2 at 1 × 10-7 M (2) and (b) Rubc3 at 3 × 10-7 M (3).

Fig S15. Overlap integral of normalized emission spectrum of ovalbumin with normalized absorption spectrum of (a) Rubc2 and (b) Rubc3.

Fig S16. Emission spectra of 1:1 mixture of ovalbumin and (a) Rubc2, (b)Rubc3 excited at 285 nm.

Fig S17. Docking of Rubc3 with ovalbumin (a) full view (b) closer view of the Ru(II) complex docked in protein.

Fig S18. Interaction of BSA (domain I, green) with t-butyl groups (purple and red) of calixarene moiety of (a) Rubc2 and (b) Rubc3.

Fig S19. Interaction of ovalbumin (green) with t-butyl groups (blue and purple) of calixarene moiety of (a) Rubc2 and (b) Rubc3.

Table S1. Interaction and distances of protein residues with t-butyl groups of Rubc2 and Rubc3.

Rubc2 / Rubc3
Residue / Distance (Å) / Residue / Distance (Å)
BSA
ARG186 / 4.77 / GLY189 / 3.59
ARG186 / 3.62 / LYS190 / 3.92
LEU182 / 2.49 / ASP183 / 4.83
LYS190 / 3.91 / LEU185 / 3.24
ASP187 / 5.11
Ovalbumin
LEU101 / 4.76 / GLY128 / 5.10
GLY127 / 2.61 / SER100 / 3.93
GLN152 / 4.10 / LEU101 / 3.06
SER151 / 3.49 / ALA37 / 3.98
ALA102 / 3.47