Interaction of Styrylcyanine Dyes with Human Serum Albumin: a Spectroscopic Study

The mechanisms of interaction of styrylcyanine dyes Sbt ((E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]thiazol-3-ium iodide), Sbo ((E)-2-(4-(dimethylamino)styryl)-3-methylbenzo[d]oxazol-3-ium iodide), Sil ((E)-2-(4-(dimethylamino)styryl)-1,3,3-trimethyl-3H-indolium perchlorate) and their homodimers Dbt-10, Dbo-10, Dil-10 with human serum albumin were studied by time-resolved fluorescence spectroscopy. A significant increase in the fluorescence quantum yield of the homodimer dyes upon their binding to human serum albumin was found. The binding constants (K_b) of these dyes to albumin were determined and were found to depend on the molecular structure of the probes. The preferred binding sites of the studied dyes within the albumin globule were identified. Molecular modeling results showed that hydrophobic interactions and hydrogen bonds with amino acid residues of the protein play a key role in stabilizing the complexes.

1. Y.-J. Hu, Y. Liu, X.-H. Xiao. Biomacromolecules, 10 (2009) 517—521, https://doi.org/10.1021/bm8014522

2. M. Fasano, S. Curry, E. Terreno, M. Galliano, G. Fanali, P. Narciso, S. Notari, P. Ascenzi. IUBMB Life, 57 (2005) 787—796, https://doi.org/10.1080/15216540500404093

3. S. H. Murch, A. D. Phillips, J. A. Walker-Smith, P. J. D. Winyard, N. Meadows, S. Koletzko, B. Wehner, H. A. Cheema, R. A. Risdon, J. Klein. Lancet, 347 (1996) 1299—1301, https://doi.org/10.1016/s0140-6736(96)90941-1

4. J. C. Seegmiller, D. R. Barnidge, B. E. Burns, T. S. Larson, J. C. Lieske, R. Kumar. Clin. Chem., 55 (2009) 1100—1107, https://doi.org/10.1373/clinchem.2008.115543

5. J. C. Seegmiller, D. Sviridov, T. S. Larson, T. M. Borland, G. L. Hortin, J. C. Lieske. Clin. Chem., 55 (2009) 1991—1994, https://doi.org/10.1373/clinchem.2009.129833

6. S. Gao, G. Wei, S. Zhang, B. Zheng, J. Xu, G. Chen, M. Li, S. Song, W. Fu, Z. Xiao, W. Lu. Nat. Commun., 10 (2019) 2206, https://doi.org/10.1038/s41467-019-10056-9

7. Y. Yu, Q.-T. Gong, W.-F. Lu, Y.-H. Liu, Z.-J. Yang, N. Wang, X.-Q. Yu. ACS Appl. Bio Mater., 3 (2020) 5193—5201, https://doi.org/10.1021/acsabm.0c00589

8. S. Pei, J. Li, N. Kang, G. Zhang, B. Zhang, C. Zhang, S. Shuang. Anal. Chim. Acta, 1190 (2022) 339267, https://doi.org/10.1016/j.aca.2021.339267

9. N. I. Wickramasinghe, B. Corbin, D. Y. Kanakarathna, Y. Pang, C. S. Abeywickrama, K. J. Wijesinghe. Biosensors, 13 (2023) 799, https://doi.org/10.3390/bios13080799

10. A. Sh. Yarmukhamedov, E. N. Kurtaliev, I. Khairov, N. Nizomov, M. R. Malikov. High Energy Chemistry, 59 (2025) 343—351, https://doi.org/10.1134/S0018143925600144

11. A. Sh. Yarmukhamedov, E. N. Kurtaliev, I. Khairov, N. Nizomov. J. Fluoresc., 36 (2026) 1243—1259, https://doi.org/10.1007/s10895-025-04634-y

12. А. Ш. Ярмухамедов, Э. Н. Курталиев, И. Д. Хаиров, Н. Низомов. Журн. прикл. cпектр., 92, № 6 (2025) 793—801 [A. Sh. Yarmukhamedov, E. N. Kurtaliev, I. D. Khairov, N. Nizomov. J. Appl. Spectrosc., 92 (2026) 1259—1267, https://doi.org/10.1007/s10812-026-02034-z]

13. V. B. Kovalska, D. V. Kryvorotenko, A. O. Balanda, M. Yu. Losytskyy, V. P. Tokar, S. M. Yar-moluk. Dyes Pigm., 67 (2005) 47—54, https://doi.org/10.1016/j.dyepig.2004.10.007

14. N. Nizomov, E. N. Kurtaliev, Sh. N. Nizamov, G. Khodjayev. J. Mol. Struct., 936 (2009) 199—205, https://doi.org/10.1016/j.molstruc.2009.07.040

15. J. R. Lakowicz. Principles of Fluorescence Spectroscopy, New York, Springer (2006), https://doi.org/10.1007/978-0-387-46312-4

16. M. Morri, D. S. Goodsell, R. S. Halliday, R. Huey, W. E. Hart, R. K. Belew, A. J. Olson. J. Comput. Chem., 19 (1989) 1639—1662, https://doi.org/10.1002/(SICI)1096-987X(19981115)19:14%3C1639::AIDJCC10%3E3.0.CO;2-B

17. S. Sugio, A. Kashima, S. Mochizuki, M. Noda, K. Kobayashi. Protein Eng., 12 (1999) 439—446, https://doi.org/10.1093/protein/12.6.439

18. A. Özdemir, E. Gökoğlu, E. Yılmaz, E. Yalçın, E. Gökoğlu, Z. Seferoğlu, T. Tekinay. Luminescence, 31 (2016) 86—92, https://doi.org/10.1002/bio.3153

19. P. Bolel, N. Mahapatra, M. Halder. J. Agric. Food Chem., 60 (2012) 3727—3734, https://doi.org/10.1021/jf205219w

20. R. Chinnappan, T. Ahmad Mir, S. Easwaramoorthi, G. Gopika Sunil, A. Feba, B. Kanagasabai, S. I. Wani, M. N. Sandouka, A. Alzhrani, S. Devanesan, M. S. Mohamad AlSalhi, N. K. Mani, W. AlKattan, A. Yaqinuddin, A. M. Abdullah Assiri, D. C. Broering. Sens. Int., 6 (2025) 100304—100312, https://doi.org/10.1016/j.sintl.2024.100304

21. J. Ghuman, P. A. Zunszain, I. Petitpas, A. A. Bhattacharya, M. Otagiri, S. Curry. J. Mol. Biol., 353 (2005) 38—52, https://doi.org/10.1016/j.jmb.2005.07.075