Chemoenzymatic Synthesis of Cryptophycin Anticancer Agents by an Ester Bond-Forming Non-ribosomal Peptide Synthetase Module
Abstract
Cryptophycins (Crp) are a group of cyanobacterial depsipeptides with activity against drug-resistant tumors. Although they have been shown to be promising, further efforts are required to return these highly potent compounds to the clinic through a new generation of analogues with improved medicinal properties. Herein, we report a chemosynthetic route relying on themultifunctional enzyme CrpD-M2 that incorporates a 2-hydroxy acid moiety (unit D) into Crp analogues. CrpD-M2 is a unique nonribosomal peptide synthetase (NRPS) module comprised of condensation-adenylation-ketoreduction-thiolation (C-A-KR-T) domains. We interrogated A-domain 2-keto and 2-hydroxy acid activation and loading, and KR domain activity in the presence of NADPH and NADH. The resulting 2-hydroxy acid was elongated with three synthetic Crp chain elongation intermediate analogues through ester bond formation catalyzed by CrpD-M2 C domain. Finally, the enzyme-bound seco-Crp products were macrolactonized by the Crp thioesterase. Analysis of these sequential steps was enabled through LC-FTICR-MS of enzyme-bound intermediates and products. This novel chemoenzymatic synthesis of Crp involves four sequential catalytic steps leading to the incorporation of a 2-hydroxy acid moiety in the final chain elongation intermediate. The presented work constitutes the first example where a NRPS-embedded KR domain is employed for assembly of a fully elaborated natural product, and serves as a proof-of-principle for chemoenzymatic synthesis of new Crp analogues.
Additional Information
© 2011 American Chemical Society. Received: May 23, 2011. Publication Date (Web): August 8, 2011. Y.D. was supported by a Rackham Predoctoral Fellowship. This work was supported by NIH grant CA108874, GM076477 and the Hans W. Vahlteich Professorship (toD.H.S.).Work in K.H.'s laboratory is supported by an NSF Career Award (CHE-05-47699).Attached Files
Supplemental Material - ja204716f_si_001.pdf
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Additional details
- Eprint ID
- 27538
- Resolver ID
- CaltechAUTHORS:20111101-073439037
- Rackham Predoctoral Fellowship
- CA108874
- NIH
- GM076477
- NIH
- Hans W. Vahlteich Professorship
- CHE-05-47699
- NSF Career Award
- Created
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2011-11-01Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field