Intramolecular sensitization and structure of a Tb$^{3+}$/2-hydroxyquinoline conjugate in the paraoxonase 1 active site

Smerkolj, Janez (author), Bahun, Miha (author), Poklar Ulrih, Nataša (author), Bavec, Aljoša (author), Pavšič, Miha (author), Goličnik, Marko (author)

Paraoxonase 1 (PON1) is a Ca$^{2+}$-dependent enzyme involved in oxidative stress processes and is widely studied for its protective roles in various diseases. Intermolecular sensitization of lanthanide ions was implemented by replacing Ca$^{2+}$ ions from the recombinant PON1 (rePON1) catalytic site in the presence of 2-hydroxyquinoline (2HQ) as an external antenna. Although the replacement of Ca$^{2+}$ ions with lanthanide ions indicates weaker binding affinity for the coordination of 2HQ in the protein milieu of the rePON1 active site, it results in the formation of a highly emissive supramolecular complex in the case of Tb$^{3+}$ ions. The architecture of the ternary rePON1 : Tb$^{3+}$ : 2HQ conjugate, which allows efficient terbium sensitization and its specific long-wavelength metal phosphorescence emission, was resolved by X-ray crystallography. These findings could establish a non-catalytic quantification strategy for PON1 and provide additional structural insights into lanthanide substitution in this Ca$^{2+}$-dependent enzyme.

• Language: English
• Keywords: intramolecular sensitization, structure of a conjugate, paraoxonase 1
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: MF - Faculty of Medicine; BF - Biotechnical Faculty; FKKT - Faculty of Chemistry and Chemical Technology
• Publication status: Published
• Publication version: Version of Record
• Year: 2025
• Number of pages: Str. 12471-12481
• Numbering: Vol. 54, iss. 33
• PID: 20.500.12556/RUL-178383
• UDC: 577
• ISSN on article: 1477-9234
• DOI: 10.1039/d5dt01484k
• COBISS.SI-ID: 249471491
• Publication date in RUL: 26.01.2026

Record is a part of a journal

• Title: Dalton transactions
• Shortened title: Dalton trans
• Publisher: Royal Society of Chemistry
• ISSN: 1477-9234
• COBISS.SI-ID: 519833113

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• License: CC BY-NC 3.0, Creative Commons Attribution-NonCommercial 3.0 Unported
• Link: http://creativecommons.org/licenses/by-nc/3.0/
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Secondary language

• Language: Slovenian
• Keywords: intramolekularna senzibilizacija, struktura konjugata, paraoksonaza ​​1