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Magin IM, Pushkin IA, Ageeva AA, Martianova SO, Polyakov NE, Doktorov AB, Leshina TV. Impact of Non-Covalent Interactions of Chiral Linked Systems in Solution on Photoinduced Electron Transfer Efficiency. Int J Mol Sci 2023; 24:ijms24119296. [PMID: 37298248 DOI: 10.3390/ijms24119296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
It is well-known that non-covalent interactions play an essential role in the functioning of biomolecules in living organisms. The significant attention of researchers is focused on the mechanisms of associates formation and the role of the chiral configuration of proteins, peptides, and amino acids in the association. We have recently demonstrated the unique sensitivity of chemically induced dynamic nuclear polarization (CIDNP) formed in photoinduced electron transfer (PET) in chiral donor-acceptor dyads to non-covalent interactions of its diastereomers in solutions. The present study further develops the approach for quantitatively analyzing the factors that determine the association by examples of dimerization of the diastereomers with the RS, SR, and SS optical configurations. It has been shown that, under the UV irradiation of dyads, CIDNP is formed in associates, namely, homodimers (SS-SS), (SR-SR), and heterodimers (SS-SR) of diastereomers. In particular, the efficiency of PET in homo-, heterodimers, and monomers of dyads completely determines the forms of dependences of the CIDNP enhancement coefficient ratio of SS and RS, SR configurations on the ratio of diastereomer concentrations. We expect that the use of such a correlation can be useful in identifying small-sized associates in peptides, which is still a problem.
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Affiliation(s)
- Ilya M Magin
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
| | - Ivan A Pushkin
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Aleksandra A Ageeva
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Sofia O Martianova
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, 630090 Novosibirsk, Russia
| | - Nikolay E Polyakov
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
| | - Alexander B Doktorov
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
| | - Tatyana V Leshina
- Voevodsky Institute of Chemical Kinetics and Combustion, 630090 Novosibirsk, Russia
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McCaslin TG, Pagba CV, Hwang H, Gumbart JC, Chi SH, Perry JW, Barry BA. Tyrosine, cysteine, and proton coupled electron transfer in a ribonucleotide reductase-inspired beta hairpin maquette. Chem Commun (Camb) 2019; 55:9399-9402. [PMID: 31322154 DOI: 10.1039/c9cc04067f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tyrosine residues act as intermediates in proton coupled electron transfer reactions (PCET) in proteins. For example, in ribonucleotide reductase (RNR), a tyrosyl radical oxidizes an active site cysteine via a 35 Å pathway that contains multiple aromatic groups. When singlet tyrosine is oxidized, the radical becomes a strong acid, and proton transfer reactions, which are coupled with the redox reaction, may be used to control reaction rate. Here, we characterize a tyrosine-containing beta hairpin, Peptide O, which has a cross-strand, noncovalent interaction between its single tyrosine, Y5, and a cysteine (C14). Circular dichroism provides evidence for a thermostable beta-turn. EPR spectroscopy shows that Peptide O forms a neutral tyrosyl radical after UV photolysis at 160 K. Molecular dynamics simulations support a phenolic/SH interaction in the tyrosine singlet and radical states. Differential pulse voltammetry exhibits pH dependence consistent with the formation of a neutral tyrosyl radical and a pKa change in two other residues. A redox-coupled decrease in cysteine pKa from 9 (singlet) to 6.9 (radical) is assigned. At pD 11, picosecond transient absorption spectroscopy after UV photolysis monitors tyrosyl radical recombination via electron transfer (ET). The ET rate in Peptide O is indistinguishable from the ET rates observed in peptides containing a histidine and a cyclohexylalanine (Cha) at position 14. However, at pD 9, the tyrosyl radical decays via PCET, and the decay rate is slowed, when compared to the histidine 14 variant. Notably, the decay rate is accelerated, when compared to the Cha 14 variant. We conclude that redox coupling between tyrosine and cysteine can act as a PCET control mechanism in proteins.
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Affiliation(s)
- Tyler G McCaslin
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA. and The Parker H. Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Cynthia V Pagba
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA. and The Parker H. Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Hyea Hwang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - James C Gumbart
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA. and The Parker H. Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA and School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - San-Hui Chi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA. and Center of Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Joseph W Perry
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA. and Center of Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Bridgette A Barry
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA. and The Parker H. Petit Institute of Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA 30332, USA
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