Serum albumin as a primary non-covalent binding protein for nitro-oleic acid.

This work explores the interaction of 9/10-nitro-oleic acid (NO2-OA) with human serum albumin (HSA). The molecular mechanism of the biological action of NO2-OA is to our knowledge based on a reversible covalent reaction-Michael addition of nucleophilic amino acid residues of proteins. Since HSA is an important fatty acid transporter, a key question is whether NO2-OA can bind covalently or non-covalently to HSA, similarly to oleic acid (OA), which can interact with the FA1-FA7 binding sites of the HSA molecule. 1H NMR studies and competition analysis with OA and the drugs ibuprofen and warfarin were used to investigate a potential non-covalent binding mode. NO2-OA/HSA binding was confirmed to compete with warfarin for FA-7 with significantly higher affinity. NO2-OA competes with ibuprofen for FA-3 and FA-6, however, in contrast to the situation with warfarin, the binding affinities are not significantly different. The described interactions are based exclusively on non-covalent binding. No covalent binding of NO2-OA to HSA was detected by MS/MS. More detailed studies based on MALDI-TOF-MS and Ellman's assay indicated that HSA can be covalently modified in the presence of NO2-OA to a very limited extent. It was also shown that NO2-OA has a higher affinity to HSA than that of OA. Copyright © 2022 Elsevier B.V. All rights reserved.

Citation

Lenka Hernychova, Eleni Alexandri, Andreas G Tzakos, Martina Zatloukalová, Alexandra Primikyri, Ioannis P Gerothanassis, Lukas Uhrik, Marek Šebela, David Kopečný, Lukáš Jedinák, Jan Vacek. Serum albumin as a primary non-covalent binding protein for nitro-oleic acid. International journal of biological macromolecules. 2022 Apr 01;203:116-129

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PMID: 35063491

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