Optimized bisubstrate inhibitors for the actin N-terminal acetyltransferase NAA80

Line M Myklebust; Markus Baumann; Svein I Støve; Håvard Foyn; Thomas Arnesen; Bengt Erik Haug

doi:10.3389/fchem.2023.1202501

Optimized bisubstrate inhibitors for the actin N-terminal acetyltransferase NAA80

Front Chem. 2023 Jun 20:11:1202501. doi: 10.3389/fchem.2023.1202501. eCollection 2023.

Authors

Line M Myklebust¹, Markus Baumann^{1

2}, Svein I Støve¹, Håvard Foyn³, Thomas Arnesen^{1

3

4}, Bengt Erik Haug²

Affiliations

¹ Department of Biomedicine, University of Bergen, Bergen, Norway.
² Department of Chemistry and Centre for Pharmacy, University of Bergen, Bergen, Norway.
³ Department of Biological Sciences, University of Bergen, Bergen, Norway.
⁴ Department of Surgery, Haukeland University Hospital, Bergen, Norway.

Abstract

Acetylation of protein N-termini is one of the most common protein modifications in the eukaryotic cell and is catalyzed by the N-terminal acetyltransferase family of enzymes. The N-terminal acetyltransferase NAA80 is expressed in the animal kingdom and was recently found to specifically N-terminally acetylate actin, which is the main component of the microfilament system. This unique animal cell actin processing is essential for the maintenance of cell integrity and motility. Actin is the only known substrate of NAA80, thus potent inhibitors of NAA80 could prove as important tool compounds to study the crucial roles of actin and how NAA80 regulates this by N-terminal acetylation. Herein we describe a systematic study toward optimizing the peptide part of a bisubstrate-based NAA80 inhibitor comprising of coenzyme A conjugated onto the N-terminus of a tetrapeptide amide via an acetyl linker. By testing various combinations of Asp and Glu which are found at the N-termini of β- and γ-actin, respectively, CoA-Ac-EDDI-NH₂ was identified as the best inhibitor with an IC₅₀ value of 120 nM.

Keywords: N-terminal acetylation; NAA80; acetyltransferase; actin; bisubstrate inhibitor; coenzyme A; cytoskeleton.

Grants and funding

The peptide synthesis laboratory at the Department of Chemistry at the University of Bergen is funded by the Trond Mohn Foundation. The Norwegian NMR Platform (NNP) is funded by the Research Council of Norway (226244/F50). This work was supported by grants from the Trond Mohn Foundation to LM.M, the Research Council of Norway (RCN) (FRIPRO Grants 249843 and 325142 to TA), the Norwegian Health Authorities of Western Norway (F-12540 to TA), the Norwegian Cancer Society (171752-PR-2009-0222 to TA), and the European Research Council (ERC) under the European Union Horizon 2020 Research and Innovation Program (Grant 772039 to TA).