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Ulyanova V, Nadyrova A, Dudkina E, Kuznetsova A, Ahmetgalieva A, Faizullin D, Surchenko Y, Novopashina D, Zuev Y, Kuznetsov N, Ilinskaya O. Structural and Functional Differences between Homologous Bacterial Ribonucleases. Int J Mol Sci 2022; 23:ijms23031867. [PMID: 35163789 PMCID: PMC8837141 DOI: 10.3390/ijms23031867] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Revised: 01/28/2022] [Accepted: 02/04/2022] [Indexed: 02/04/2023] Open
Abstract
Small cationic guanyl-preferring ribonucleases (RNases) produced by the Bacillus species share a similar protein tertiary structure with a high degree of amino acid sequence conservation. However, they form dimers that differ in conformation and stability. Here, we have addressed the issues (1) whether the homologous RNases also have distinctions in catalytic activity towards different RNA substrates and interactions with the inhibitor protein barstar, and (2) whether these differences correlate with structural features of the proteins. Circular dichroism and dynamic light scattering assays revealed distinctions in the structures of homologous RNases. The activity levels of the RNases towards natural RNA substrates, as measured spectrometrically by acid-soluble hydrolysis products, were similar and decreased in the row high-polymeric RNA >>> transport RNA > double-stranded RNA. However, stopped flow kinetic studies on model RNA substrates containing the guanosine residue in a hairpin stem or a loop showed that the cleavage rates of these enzymes were different. Moreover, homologous RNases were inhibited by the barstar with diverse efficiency. Therefore, minor changes in structure elements of homologous proteins have a potential to significantly effect molecule stability and functional activities, such as catalysis or ligand binding.
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Affiliation(s)
- Vera Ulyanova
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; (A.N.); (E.D.); (A.A.); (Y.S.); (O.I.)
- Correspondence:
| | - Alsu Nadyrova
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; (A.N.); (E.D.); (A.A.); (Y.S.); (O.I.)
| | - Elena Dudkina
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; (A.N.); (E.D.); (A.A.); (Y.S.); (O.I.)
| | - Aleksandra Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.K.); (D.N.); (N.K.)
| | - Albina Ahmetgalieva
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; (A.N.); (E.D.); (A.A.); (Y.S.); (O.I.)
| | - Dzhigangir Faizullin
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (D.F.); (Y.Z.)
| | - Yulia Surchenko
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; (A.N.); (E.D.); (A.A.); (Y.S.); (O.I.)
| | - Darya Novopashina
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.K.); (D.N.); (N.K.)
| | - Yuriy Zuev
- Kazan Institute of Biochemistry and Biophysics, FRC Kazan Scientific Center of RAS, 420111 Kazan, Russia; (D.F.); (Y.Z.)
| | - Nikita Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of the Russian Academy of Sciences, 630090 Novosibirsk, Russia; (A.K.); (D.N.); (N.K.)
| | - Olga Ilinskaya
- Department of Microbiology, Institute of Fundamental Medicine and Biology, Kazan (Volga Region) Federal University, 420008 Kazan, Russia; (A.N.); (E.D.); (A.A.); (Y.S.); (O.I.)
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