Volume 131, Issue 40 pp. 14258-14262
Zuschrift

Fluorescent Isoindole Crosslink (FlICk) Chemistry: A Rapid, User-friendly Stapling Reaction

Mihajlo Todorovic

Mihajlo Todorovic

Chemistry Department, UBC, 2036 Main Mall, Vancouver, B.C., V6T1Z1 Canada

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Katerina D. Schwab

Katerina D. Schwab

Chemistry Department, UBC, 2036 Main Mall, Vancouver, B.C., V6T1Z1 Canada

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Dr. Jutta Zeisler

Dr. Jutta Zeisler

B.C. Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3 Canada

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Dr. Chengcheng Zhang

Dr. Chengcheng Zhang

B.C. Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3 Canada

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Prof. Dr. Francois Bénard

Prof. Dr. Francois Bénard

B.C. Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, BC, V5Z 1L3 Canada

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Prof. Dr. David M. Perrin

Corresponding Author

Prof. Dr. David M. Perrin

Chemistry Department, UBC, 2036 Main Mall, Vancouver, B.C., V6T1Z1 Canada

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First published: 18 June 2019
Citations: 19

Abstract

The stabilization of peptide secondary structure via stapling is a ubiquitous goal for creating new probes, imaging agents, and drugs. Inspired by indole-derived crosslinks found in natural peptide toxins, we employed ortho-phthalaldehydes to create isoindole staples, thus transforming inactive linear and monocyclic precursors into bioactive monocyclic and bicyclic products. Mild, metal-free conditions give an array of macrocyclic α-melanocyte-stimulating hormone (α-MSH) derivatives, of which several isoindole-stapled α-MSH analogues (Ki≈1 nm) are found to be as potent as α-MSH. Analogously, late-stage intra-annular isoindole stapling furnished a bicyclic peptide mimic of α-amanitin that is cytotoxic to CHO cells (IC50=70 μm). Given its user-friendliness, we have termed this approach FlICk (fluorescent isoindole crosslink) chemistry.

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