Atomic View of Aqueous Cyclosporine A: Unpacking a Decades-Old Mystery

Miranda N. Limbach; Aleksandra Antevska; Damilola S. Oluwatoba; Amber L.H. Gray; Xian B. Carroll; Christina M. Hoffmann; Xiaoping Wang; Markus W. Voehler; Carlos A. Steren; Thanh D. Do

doi:10.1021/jacs.2c01743

Atomic View of Aqueous Cyclosporine A: Unpacking a Decades-Old Mystery

Miranda N. Limbach, Aleksandra Antevska, Damilola S. Oluwatoba, Amber L.H. Gray, Xian B. Carroll, Christina M. Hoffmann, Xiaoping Wang, Markus W. Voehler, Carlos A. Steren, Thanh D. Do

Single Crystal Diffraction

Research output: Contribution to journal › Article › peer-review

9 Scopus citations

Abstract

An atomic view of a main aqueous conformation of cyclosporine A (CycA), an important 11-amino-acid macrocyclic immunosuppressant, is reported. For decades, it has been a grand challenge to determine the conformation of free CycA in an aqueous-like solution given its poor water solubility. Using a combination of X-ray and single-crystal neutron diffraction, we unambiguously resolve a unique conformer (A1) with a novel cis-amide between residues 11 and 1 and two water ligands that stabilize hydrogen bond networks. NMR spectroscopy and titration experiments indicate that the novel conformer is as abundant as the closed conformer in 90/10 (v/v) methanol/water and is the main conformer at 10/90 methanol/water. Five other conformers were also detected in 90/10 methanol/water, one in slow exchange with A1, another one in slow exchange with the closed form and three minor ones, one of which contains two cis amides Abu2-Sar3 and MeBmt1-MeVal11. These conformers help better understand the wide spectrum of membrane permeability observed for CycA analogues and, to some extent, the binding of CycA to protein targets.

Original language	English
Pages (from-to)	12602-12607
Number of pages	6
Journal	Journal of the American Chemical Society
Volume	144
Issue number	28
DOIs	https://doi.org/10.1021/jacs.2c01743
State	Published - Jul 20 2022

Funding

We thank Stephanie Steren-Ruta for help with the data organization and automation. We gratefully acknowledge the laboratory start-up research support from the University of Tennessee and Department of Chemistry, the Global Academic Support Program from Agilent, and the Advanced Computer Facility (ACF) of the University of Tennessee for computational resources. The University of Tennessee also provided additional financial support for the X-ray facility. Single-crystal neutron diffraction used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. The 900 MHz spectrometer is supported by a grant for NMR instrumentation from the NSF (0922862) and Vanderbilt University matching funds.

Funders	Funder number
National Science Foundation	0922862
Vanderbilt University
University of Tennessee
Department of Chemistry, University of York

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title = "Atomic View of Aqueous Cyclosporine A: Unpacking a Decades-Old Mystery",

abstract = "An atomic view of a main aqueous conformation of cyclosporine A (CycA), an important 11-amino-acid macrocyclic immunosuppressant, is reported. For decades, it has been a grand challenge to determine the conformation of free CycA in an aqueous-like solution given its poor water solubility. Using a combination of X-ray and single-crystal neutron diffraction, we unambiguously resolve a unique conformer (A1) with a novel cis-amide between residues 11 and 1 and two water ligands that stabilize hydrogen bond networks. NMR spectroscopy and titration experiments indicate that the novel conformer is as abundant as the closed conformer in 90/10 (v/v) methanol/water and is the main conformer at 10/90 methanol/water. Five other conformers were also detected in 90/10 methanol/water, one in slow exchange with A1, another one in slow exchange with the closed form and three minor ones, one of which contains two cis amides Abu2-Sar3 and MeBmt1-MeVal11. These conformers help better understand the wide spectrum of membrane permeability observed for CycA analogues and, to some extent, the binding of CycA to protein targets.",

author = "Limbach, {Miranda N.} and Aleksandra Antevska and Oluwatoba, {Damilola S.} and Gray, {Amber L.H.} and Carroll, {Xian B.} and Hoffmann, {Christina M.} and Xiaoping Wang and Voehler, {Markus W.} and Steren, {Carlos A.} and Do, {Thanh D.}",

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AU - Gray, Amber L.H.

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AU - Hoffmann, Christina M.

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AU - Do, Thanh D.

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Atomic View of Aqueous Cyclosporine A: Unpacking a Decades-Old Mystery

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