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Nostocyclopeptides as new inhibitors of 20s proteasome.

Fidor, Anna; Cekała, Katarzyna; Wieczerzak, Ewa; Cegłowska, Marta; Kasprzykowski, Franciszek; Edwards, Christine; Mazur-Marzec, Hanna


Anna Fidor

Katarzyna Cekała

Ewa Wieczerzak

Marta Cegłowska

Franciszek Kasprzykowski

Hanna Mazur-Marzec


Nostocyclopeptides (Ncps) are a small class of bioactive nonribosomal peptides produced solely by cyanobacteria of the genus Nostoc. In the current work, six Ncps were isolated from Nostoc edaphicum strain CCNP1411. The bioactivity of these compounds was tested in vitro against 20S proteasome, a proteolytic complex that plays an important role in maintaining cellular proteostasis. Dysfunction of the complex leads to many pathological disorders. The assays indicated selective activity of specific Ncp variants. For two linear peptide aldehydes, Ncp-A2-L and Ncp-E2-L, the inhibitory effects on chymotrypsin-like activity were revealed, while the cyclic variant, Ncp-A2, inactivated the trypsin-like site of this enzymatic complex. The aldehyde group was confirmed to be an important element of the chymotrypsin-like activity inhibitors. The nostocyclopeptides, as novel inhibitors of 20S proteasome, increased the number of natural products that can be considered potential regulators of cellular processes.


FIDOR, A., CEKAŁA, K., WIECZERZAK, E., CEGŁOWSKA, M., KASPRZYKOWSKI, F., EDWARDS, C. and MAZUR-MARZEC, H. 2021. Nostocyclopeptides as new inhibitors of 20S proteasome. Biomolecules [online], 11(10), article 1483. Available from:

Journal Article Type Article
Acceptance Date Oct 5, 2021
Online Publication Date Oct 8, 2021
Publication Date Oct 31, 2021
Deposit Date Oct 11, 2021
Publicly Available Date Oct 11, 2021
Journal Biomolecules
Publisher MDPI
Peer Reviewed Peer Reviewed
Volume 11
Issue 10
Article Number 1483
Keywords 20S proteasome inhibitors; Cyanobacteria; Nostoc; Nostocyclopeptides
Public URL
Additional Information The accompanying file contains supplementary figures which can be found at the end of the main text.


FIDOR 2021 Nostocyclopeptides (VOR) (1.3 Mb)

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Copyright Statement
© 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (

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