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Sahoo BK, Velavalapalli VM. Assessing Partial Inhibition of Ribonuclease A Activity by Curcumin through Fluorescence Spectroscopy and Theoretical Studies. J Fluoresc 2023:10.1007/s10895-023-03474-y. [PMID: 37870732 DOI: 10.1007/s10895-023-03474-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 10/12/2023] [Indexed: 10/24/2023]
Abstract
Molecular interactions and controlled expression of enzymatic activities are fundamental to all cellular functions in an organism. The active polyphenol in turmeric known as curcumin (CCM) is known to exhibit diverse pharmacological activities. Ribonucleases (RNases) are the hydrolytic enzymes that plays important role in ribonucleic acid (RNA) metabolism. Uncontrolled and unwanted cleavage of RNA by RNases may be the cause of cell death leading to disease states. The protein ribonuclease A (RNase A) in the superfamily of RNases cleaves the RNA besides its role in different diseases like autoimmune diseases, and pancreatic disorders. Interaction of CCM with RNase A have been reported along with the possible role of CCM to inhibit the RNase A enzymatic activity. The interaction strength was found to be 104 M-1 order from spectroscopic results. Quenching of RNase A fluorescence by CCM was 104 M-1 order. Non-radiative energy transfer from RNase A (donor) to CCM (acceptor) suggested a distance of 2.42 nm between the donor-acceptor pair. Circular dichroism studies revealed no structural changes in RNase A after binding. Binding-induced conformational variation in protein was observed from synchronous fluorescence studies. Agarose gel electrophoresis revealed a partial inhibition of the RNase A activity by CCM though not significant. Molecular docking and molecular dynamics studies suggested the residues of RNase A involved in the interaction with supporting the experimental finding for the partial inhibition of the enzyme activity. This study may help in designing new CCM analogues or related structures to understand their differential inhibition of the RNase A activity.
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Affiliation(s)
- Bijaya Ketan Sahoo
- Department of Chemistry, School of Science, GITAM Deemed to be University, Hyderabad, 502329, India.
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Musiyak VV, Nizova IA, Chulakov EN, Sadretdinova LS, Tumashov AA, Levit GL, Krasnov VP. Stereochemical aspects in the synthesis of novel N-(purin-6-yl)dipeptides as potential antimycobacterial agents. Amino Acids 2021; 53:407-415. [PMID: 33599833 PMCID: PMC7889712 DOI: 10.1007/s00726-021-02958-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 02/06/2021] [Indexed: 11/08/2022]
Abstract
The synthesis of purine conjugates with natural amino acids is one of the promising directions in search for novel therapeutic agents, including antimycobacterial agents. The purpose of this study was to synthesize N-(purin-6-yl)dipeptides containing the terminal fragment of (S)-glutamic acid. To obtain the target compounds, two synthetic routes were tested. The first of them is based on coupling of N-(purin-6-yl)-(S)-amino acids to dimethyl (S)-glutamate in the presence of carbodiimide coupling agent followed by the removal of ester groups. However, it turned out that this coupling process was accompanied by racemization of the chiral center of N-(purin-6-yl)-α-amino acids and in all cases led to mixtures of (S,S)- and (R,S)-diastereomers (6:4). Individual (S,S)-diastereomers were obtained using an alternative approach based on the nucleophilic substitution of chlorine in 6-chloropurine or 2-amino-6-chloropurine with corresponding dipeptides as nucleophiles. The enantiomeric purity of the target compounds was confirmed by chiral HPLC. To test the assumption that racemization of the chiral center of N-(purin-6-yl)-α-amino acids occurs with the participation of nitrogen atoms of the imidazole ring via the stage of formation of a chirally labile intermediate, we obtained such structural analogs of N-(purin-6-yl)-(S)-alanine as N-(9-benzylpurin-6-yl)-(S)-alanine and N-(7-deazapurin-6-yl)-(S)-alanine. It was found that coupling of these compounds to dimethyl (S)-glutamate was also accompanied by racemization. This indicates that the imidazole fragment does not play a crucial role in this process. When testing the antimycobacterial activity of some of the obtained compounds, conjugates with moderate activity against the laboratory Mycobacterium tuberculosis H37Rv strain (MIC 3.1–6.25 μg/mL) were identified.
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Affiliation(s)
- Vera V Musiyak
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia
| | - Irina A Nizova
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia
| | - Evgeny N Chulakov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia
| | - Liliya Sh Sadretdinova
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia
| | - Andrey A Tumashov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia.,Ural Federal University, 19, Mira St., Ekaterinburg, 620002, Russia
| | - Galina L Levit
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia
| | - Victor P Krasnov
- Postovsky Institute of Organic Synthesis of RAS (Ural Branch), 22/20, S. Kovalevskoy/Akademicheskaya St., Ekaterinburg, 620108, Russia. .,Ural Federal University, 19, Mira St., Ekaterinburg, 620002, Russia.
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