Unraveling the stability of plasma proteins upon interaction of synthesized uridine products: biophysical and molecular dynamics approach

Abstract

Most of the drugs binding to human serum albumin (HSA) are transported to various parts of the body. Here, we have studied the molecular interaction between HSA and synthesized uridine derivatives, 1-[(3R, 4S, 5 R)-2-methyl-3, 4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]pyrimidine-2,4-dion.)(C-MU); [(2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-3,4-dihydroxy-4-methyl-tetrahydrofuran-2-yl] methyl methyl phosphochloridate (CM-MU) and [(2R,3S,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-2-methyl-3,4-dihydroxyoxolan-2-yl] methyl dihydrogen phosphate (P-MU). Cytotoxic studies of these synthesized compounds with mouse macrophages (RAW 246.7) and HeLa cells (human cervical cancer cells) and binding mechanism of these uridine derivatives with HSA were performed. Subsequently, fluorescence quenching was observed upon titration of uridine derivatives with HSA via static mode of quenching, and the binding constants (K_2-C-MU = 4 ± 0.03 × 10⁴M⁻¹, K_5-CM-MU = 1.95 ± 0.03 × 10⁴ M⁻¹ and K_5-P-MU =1.56 ± 0.03 × 10⁴ M⁻¹) were found to be in sync with the computational results. Further, molecular displacement and molecular docking data revealed that all the derivatives are binding in the subdomain IIA and IIB regions of HSA. The protein secondary structure of complexes was determined by circular dichroism, indicating partial unfolding of the protein upon addition of the uridine derivatives. Furthermore, atomic force microscopy data reveal the change in topology upon binding of 2-C-MU, 5-CM-MU and 5-P-MU with HSA, indicating change in the microenvironment around tryptophan region. Additionally, cytotoxicity studies on HeLa and Raw Cell lines suggested that these molecules have significant anti-proliferative and anti-inflammatory properties. Hence, the study may be of help for development of new drugs based on uridine derivatives which may be helpful for combating various potential diseases.

Communicated by Ramaswamy H. Sarma

Keywords:

• Drug binding
• human serum albumin
• molecular dynamics simulations
• MTT assay
• protein conformation
• uridine derivatives

Acknowledgements

We thank BIF, University of Hyderabad, for Bioinformatics facilities and also acknowledge the AFM facility provided by the School of Chemistry, University of Hyderabad.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

This work was supported by Science and Engineering Research Board [SB/EMEQ-064/2014 dated 14-07-2015 and DST-FIST], DST-FIST, UGC-SAP and UPE-2 University of Hyderabad. SD acknowledges CSIR for providing financial support.