Targeting anti-apoptotic Bcl2 proteins with scyllatoxin-based BH3 domain mimetics

Harris, Mike; Coon, Zachary; Alqaeisoom, Najah; Swords, Brian; Holub, Justin M.

doi:10.1039/c5ob02080h

Cited by 11 publications

(34 citation statements)

References 31 publications

(51 reference statements)

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“…Extensive structure-activity relationship studies carried out on disulfide-rich sequences derived from animal venoms have led to approved drugs (e.g., ziconotide for chronic pain, hirudin for anticoagulation) as well as a number of compounds in clinical development. [2] Expanding beyond their natural functions, disulfide-rich scaffolds have also been engineered as de novo ligands for protein surfaces, [3] with sequences derived from rational design, [4] computational, [5] as well as directed evolution approaches. [6] …”

Section: Introductionmentioning

confidence: 99%

Heterogeneous‐Backbone Foldamer Mimics of a Computationally Designed, Disulfide‐Rich Miniprotein

2018

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Disulfide-rich peptides have found widespread use in the development of bioactive agents; however, low proteolytic stability and difficulty exerting synthetic control over chain topology present barriers to applications in some systems. Here, we report a method that enables creation of artificial backbone (“foldamer”) mimics of compact, disulfide-rich tertiary folds. Systematic replacement of a subset of natural α-residues with various artificial building blocks in the context of a computationally designed prototype sequence leads to “heterogeneous-backbone” variants that undergo clean oxidative folding, adopt tertiary structures indistinguishable from the prototype, and enjoy proteolytic protection beyond that inherent to the topologically constrained scaffold. Collectively, these results demonstrate systematic backbone substitution as a viable method to engineer the properties of disulfide-rich sequences and expands the repertoire of protein mimicry by foldamers to an exciting new structural class.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous‐Backbone Foldamer Mimics of a Computationally Designed, Disulfide‐Rich Miniprotein

2018

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“…Surprisingly, we found that ScTx-based BH3 domain mimetics containing three disulfide linkages did not bind Bcl-2 in vitro [24]. However, removing all three disulfides rescued the ability for ScTx-based BH3 domain mimetics to target Bcl-2 proteins with submicromolar affinity, indicating that an induced-fit binding mechanism is required for favorable BH3:Bcl2 interactions [24,28]. These findings prompted us to explore how discrete structural elements, such as individual disulfide linkages, affected the folding and activity of ScTx-based BH3 domain mimetics.…”

Section: Introductionmentioning

confidence: 80%

“…Furthermore, ScTx contains three disulfides that contribute to its folded structure; each of these disulfides can, in theory, be added or removed depending on the structural requirements of the molecular interaction being investigated. Surprisingly, we found that ScTx-based BH3 domain mimetics containing three disulfide linkages did not bind Bcl-2 in vitro [24]. However, removing all three disulfides rescued the ability for ScTx-based BH3 domain mimetics to target Bcl-2 proteins with submicromolar affinity, indicating that an induced-fit binding mechanism is required for favorable BH3:Bcl2 interactions [24,28].…”

Section: Introductionmentioning

confidence: 85%

“…We have recently reported a miniature protein design strategy in which residues of the BH3 domain of the pro-apoptotic Bcl-2 protein Bax were grafted to the α-helix of scyllatoxin (ScTx) [24]. ScTx is a 31-amino acid protein that folds into an α/β structural motif stabilized by three disulfide linkages between cysteines C3-C21, C8-C26 and C12-C28 [25].…”

Section: Introductionmentioning

confidence: 99%

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Role of single disulfide linkages in the folding and activity of scyllatoxin-based BH3 domain mimetics

et al. 2017

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Anti-apoptotic Bcl-2 proteins are implicated in pathogenic cell survival and have attracted considerable interest as therapeutic targets. We recently developed a class of synthetic peptide based on scyllatoxin (ScTx) designed to mimic the helical BH3 interaction domain of the pro-apoptotic Bcl-2 protein Bax. In this communication, the contribution of single disulfides in the folding and function of ScTx-Bax peptides was investigated. We synthesized five ScTx-Bax variants, each presenting a different combination of native disulfide linkage and evaluated their ability to directly bind Bcl-2 in vitro. It was determined that the position of the disulfide linkage had significant implications on the structure and function of ScTx-Bax peptides. This study underscores the importance of structural dynamics in BH3:Bcl-2 interactions and further validates ScTx-based ligands as potential modulators of anti-apoptotic Bcl-2 function. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

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“…These data would suggest that the helical content of the ligand is not sufficient to induce a cellular response: Indeed, 10 and 13 possess higher helical content than 5, but contrarily to the latter, they had no effect on the cells. This might be due to an unfavorable interaction pattern displayed by the cyclopeptide (Figure S7) or to a loss of conformational dynamics: In this regard, it has been recently reported that the highly rigid three-disulfidebonded scyllatoxin was not suitable for protein grafting and Bcl-2 protein targeting; however, its reduced form was, suggesting the importance of induced fit mechanisms in binding to the Bcl-2 protein [82].…”

Section: Discussionmentioning

confidence: 99%

Impact of the amino acid sequence on the conformation of side chain lactam‐bridged octapeptides

Neukirchen

Krieger

Roschger

et al. 2017

Journal of Peptide Science

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Synthetic helical peptides are valuable scaffolds for the development of modulators of protein-protein interactions involving helical motifs. Backbone-to-side chain or side chain-to-side chain constraints have been and still are intensively exploited to stabilize short α-helices. Very often, these constraints have been combined with backbone modifications induced by Cα-tetrasubstituted, β-, or γ-amino acids, which facilitate the α-peptide or α/β/γ-peptide adopting an α-helical conformation. In this work, we investigated the helical character of octapeptides that were cyclized by a Lys-Asp-(i,i + 4)-lactam bridge. We started with two sequences extracted from the helix-loop-helix region of the Id proteins, which are inhibitors of cell differentiation during development and in cancer. Nineteen analogs containing the lactam bridge at different positions and displaying different amino acid core triads (i + 1,2,3) as well as outer residues were prepared by solid-phase methodology. Their conformation in water and water/2,2,2-trifluoroethanol mixtures was investigated by circular dichroism (CD) spectroscopy. The cyclopeptides could be grouped in helix-prone and non-helix-prone structures. Both the amino acid core triad (i + 1,2,3) and the pendant residues positively or negatively affected the formation of a helical structure. Computational studies based on the NMR-derived helical structure of a cyclopeptide containing Aib at position (i + 2) of the triad were generally in agreement with the secondary structure propensity of the cyclopeptides observed by CD spectroscopy. In conclusion, the Lys-Asp-(i,i + 4)-lactam bridge may succeed or fail in the stabilization of short helices, depending on the primary structure. Moreover, computational methods may be valuable tools to discriminate helix-prone from non-helix-prone peptide-based macrolactams. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

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Targeting anti-apoptotic Bcl2 proteins with scyllatoxin-based BH3 domain mimetics

Cited by 11 publications

References 31 publications

Heterogeneous‐Backbone Foldamer Mimics of a Computationally Designed, Disulfide‐Rich Miniprotein

Heterogeneous‐Backbone Foldamer Mimics of a Computationally Designed, Disulfide‐Rich Miniprotein

Role of single disulfide linkages in the folding and activity of scyllatoxin-based BH3 domain mimetics

Impact of the amino acid sequence on the conformation of side chain lactam‐bridged octapeptides

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