Exploring the Substitution of the C21-OAc Moiety in [11]Cytochalasans: Synthesis and Evaluation of Fluorophore Conjugates

Research output: Contribution to journalArticleResearchpeer review

Authors

  • Mervic D. Kagho
  • Katharina Schmidt
  • Aishi Chakrabarti
  • Marius Karger
  • Christopher Lambert
  • Maurice Hauser
  • Russell J. Cox
  • Klemens Rottner
  • Marc Stadler
  • Theresia E. Stradal
  • Philipp Klahn

External Research Organisations

  • University of Gothenburg
  • Helmholtz Centre for Infection Research (HZI)
  • Technische Universität Braunschweig
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Details

Original languageEnglish
Article numbere202500794
JournalCHEMBIOCHEM
Volume27
Issue number1
Publication statusPublished - 8 Jan 2026

Abstract

The actin cytoskeleton plays a central role in cellular organization and dynamics, yet the tools available for targeting actin function remain limited. Cytochalasans represent a large class of actin-targeting natural products that are readily cell permeable with varying cytotoxicity and actin-targeting capabilities in mammalian cells. Their pharmacologic exploitation not only requires an understanding of their mode of action but also exact knowledge of how they can be derivatized without affecting their bioactivity. Herein, the design, synthesis, and evaluation of five fluorescently labeled [11]cytochalasan derivatives generated from pyrichalasin H (PyriH) and 19,20-epoxycytochalasin C (EpoxyCytoC) are reported. Guided by molecular docking, the C21-OAc moiety is identified as a promising site for tag attachment without disrupting actin binding. Semisynthetic modifications enable the conjugation of different dyes to PyriH and EpoxyCytoC scaffolds. Moreover, the effect of linkers separating cytochalasans and dyes is analyzed. Biological evaluation supplemented by in vitro assays to additionally interrogates their activities on the assembly of pure actin filaments revealing distinct activity profiles. Together, this study compares permeability, cytotoxicity, and actin binding of five novel [11]cytochalasan probes bearing substitutions of the C21-OAc moiety. These findings establish the C21-OAc position as a versatile functionalization site and provide a framework for developing next generation cytochalasan-based actin-targeting probes.

Keywords

    actin imaging, molecular docking, semisynthesis, [11]cytochalsans

ASJC Scopus subject areas

Cite this

Exploring the Substitution of the C21-OAc Moiety in [11]Cytochalasans: Synthesis and Evaluation of Fluorophore Conjugates. / Kagho, Mervic D.; Schmidt, Katharina; Chakrabarti, Aishi et al.
In: CHEMBIOCHEM, Vol. 27, No. 1, e202500794, 08.01.2026.

Research output: Contribution to journalArticleResearchpeer review

Kagho, MD, Schmidt, K, Chakrabarti, A, Karger, M, Lambert, C, Hauser, M, Cox, RJ, Rottner, K, Stadler, M, Stradal, TE & Klahn, P 2026, 'Exploring the Substitution of the C21-OAc Moiety in [11]Cytochalasans: Synthesis and Evaluation of Fluorophore Conjugates', CHEMBIOCHEM, vol. 27, no. 1, e202500794. https://doi.org/10.1002/cbic.202500794
Kagho, M. D., Schmidt, K., Chakrabarti, A., Karger, M., Lambert, C., Hauser, M., Cox, R. J., Rottner, K., Stadler, M., Stradal, T. E., & Klahn, P. (2026). Exploring the Substitution of the C21-OAc Moiety in [11]Cytochalasans: Synthesis and Evaluation of Fluorophore Conjugates. CHEMBIOCHEM, 27(1), Article e202500794. https://doi.org/10.1002/cbic.202500794
Kagho MD, Schmidt K, Chakrabarti A, Karger M, Lambert C, Hauser M et al. Exploring the Substitution of the C21-OAc Moiety in [11]Cytochalasans: Synthesis and Evaluation of Fluorophore Conjugates. CHEMBIOCHEM. 2026 Jan 8;27(1):e202500794. doi: 10.1002/cbic.202500794
Kagho, Mervic D. ; Schmidt, Katharina ; Chakrabarti, Aishi et al. / Exploring the Substitution of the C21-OAc Moiety in [11]Cytochalasans : Synthesis and Evaluation of Fluorophore Conjugates. In: CHEMBIOCHEM. 2026 ; Vol. 27, No. 1.
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abstract = "The actin cytoskeleton plays a central role in cellular organization and dynamics, yet the tools available for targeting actin function remain limited. Cytochalasans represent a large class of actin-targeting natural products that are readily cell permeable with varying cytotoxicity and actin-targeting capabilities in mammalian cells. Their pharmacologic exploitation not only requires an understanding of their mode of action but also exact knowledge of how they can be derivatized without affecting their bioactivity. Herein, the design, synthesis, and evaluation of five fluorescently labeled [11]cytochalasan derivatives generated from pyrichalasin H (PyriH) and 19,20-epoxycytochalasin C (EpoxyCytoC) are reported. Guided by molecular docking, the C21-OAc moiety is identified as a promising site for tag attachment without disrupting actin binding. Semisynthetic modifications enable the conjugation of different dyes to PyriH and EpoxyCytoC scaffolds. Moreover, the effect of linkers separating cytochalasans and dyes is analyzed. Biological evaluation supplemented by in vitro assays to additionally interrogates their activities on the assembly of pure actin filaments revealing distinct activity profiles. Together, this study compares permeability, cytotoxicity, and actin binding of five novel [11]cytochalasan probes bearing substitutions of the C21-OAc moiety. These findings establish the C21-OAc position as a versatile functionalization site and provide a framework for developing next generation cytochalasan-based actin-targeting probes.",
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T2 - Synthesis and Evaluation of Fluorophore Conjugates

AU - Kagho, Mervic D.

AU - Schmidt, Katharina

AU - Chakrabarti, Aishi

AU - Karger, Marius

AU - Lambert, Christopher

AU - Hauser, Maurice

AU - Cox, Russell J.

AU - Rottner, Klemens

AU - Stadler, Marc

AU - Stradal, Theresia E.

AU - Klahn, Philipp

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PY - 2026/1/8

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N2 - The actin cytoskeleton plays a central role in cellular organization and dynamics, yet the tools available for targeting actin function remain limited. Cytochalasans represent a large class of actin-targeting natural products that are readily cell permeable with varying cytotoxicity and actin-targeting capabilities in mammalian cells. Their pharmacologic exploitation not only requires an understanding of their mode of action but also exact knowledge of how they can be derivatized without affecting their bioactivity. Herein, the design, synthesis, and evaluation of five fluorescently labeled [11]cytochalasan derivatives generated from pyrichalasin H (PyriH) and 19,20-epoxycytochalasin C (EpoxyCytoC) are reported. Guided by molecular docking, the C21-OAc moiety is identified as a promising site for tag attachment without disrupting actin binding. Semisynthetic modifications enable the conjugation of different dyes to PyriH and EpoxyCytoC scaffolds. Moreover, the effect of linkers separating cytochalasans and dyes is analyzed. Biological evaluation supplemented by in vitro assays to additionally interrogates their activities on the assembly of pure actin filaments revealing distinct activity profiles. Together, this study compares permeability, cytotoxicity, and actin binding of five novel [11]cytochalasan probes bearing substitutions of the C21-OAc moiety. These findings establish the C21-OAc position as a versatile functionalization site and provide a framework for developing next generation cytochalasan-based actin-targeting probes.

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