HIV-1 Tat-derived peptides as allosteric inhibitors of the proteasome activity

• Autorzy: Stoj J. , Karpowicz P. , Gaczynska M. , Osmulski P. , Jankowska E.
• Języki publikacji: EN

Abstrakty

EN

The proteasome is a main protease of the ubiquitin-proteasome pathway, responsible for degradation of the majority of intracellular proteins in human cells. Since the proteasome regulates so many processes, abnormalities in its functioning play a causal role in a number of diseases, including muscular dystrophy, cardiovascular diseases and various cancers. The ubiquitin-proteasome pathway is involved also in disorders affecting central nervous system – cerebral ischemia/reperfusion injury and stroke. This implication in pathological condition makes the proteasome an important and very promising therapeutic target. The 26S proteasome, which is responsible for ATP-dependent proteolysis of ubiquitin-tagged proteins, consists of a barrel-like core particle – the 20S proteasome, and attached to it two regulatory particles 19S. The core particle is composed of four rings (αββα). The inner β-rings harbour active sites, which display distinct specificities and are responsible for cleavages of polypeptides after hydrophobic, acidic and basic residues (Marques et al. 2009). On the other hand, N-terminal residues of α subunits create a gate leading to the catalytic chamber. Because most of the already known proteasome inhibitors are competitive they are not selective enough and can block all active sites causing cell apoptosis. We believe that allosteric modulators may be an interesting alternative to active site inhibitors. The multi-subunit and multi-active sites structure of the proteasome creates an opportunity to selective allosteric regulation of its activity. We focus our searching on biomolecules which bind to the α-ring of the 20S proteasome and influence the enzyme’s gating mechanism. HIV-1 Tat protein is one of the natural proteasome regulators competing with 11S activator for binding to the α-rings (Huang et al. 2002). We designed two peptides: G48RKKRRQRRRPS59 (Tat1) and R49KKRRQRR56Q66DPI69 (Tat2) based on a sequence of the basic domain of the protein (Jankowska et al. 2010). We found that both of them efficiently inhibit 20S proteasome. We tried to connect the biological activity of Tat peptides to their structure determined by means of CD, FTIR, NMR and molecular dynamics simulation. Additionally, we synthesized alanine scan of Tat2 to determine the importance of individual amino acids. We exchanged not only single residues but also several adjacent amino acids at once and tested the influence of these changes on the proteasome activity. We also investigated the scan peptides’ structure using FTIR. The work was supported by grants: 538-8440-1043-12, DS/8440-4- 0172-2 and NCN 2011/01/B/ST5/06616

Słowa kluczowe

EN

HIV-1; TAT peptide; allosteric inhibitor; proteasome activity; intracellular protein; human cell; muscular dystrophy; cardiovascular disease; central nervous system; pathology; cancer

• Wydawca: -
• Czasopismo: Acta Neurobiologiae Experimentalis
• Rocznik: 2013
• Tom: 73
• Numer: 1
• Opis fizyczny: p.187-188

Twórcy

autor

Stoj J.

• Faculty of Chemistry, University of Gdansk, Gdansk, Poland

autor

Karpowicz P.

• Faculty of Chemistry, University of Gdansk, Gdansk, Poland

autor

Gaczynska M.

• Institute of Biotechnology, University of Texas Health Science Center, San Antonio, Texas, USA

autor

Osmulski P.

• Institute of Biotechnology, University of Texas Health Science Center, San Antonio, Texas, USA

autor

Jankowska E.

• Faculty of Chemistry, University of Gdansk, Gdansk, Poland