Taming Conformational Heterogeneity on Ion Racetrack to Unveil Principles that Drive Membrane Permeation of Cyclosporines

• DOI: 10.1021/jacsau.4c00011
• Publication Date: 2024-03-16T18:49:13Z
• Authors: Miranda N. Limbach; Edward T. Lindberg; Hernando J. Olivos; Lara van Tetering; Carlos A. Steren; Jonathan Martens; Van A. Ngo; Jos Oomens; Thanh D. Do
• Keywords: Conformational isomerism; Infrared multiphoton dissociation; Membrane permeability; Ion-mobility spectrometry

Our study reveals the underlying principles governing passive membrane permeability in three large N-methylated macrocyclic peptides (N-MeMPs): cyclosporine A (CycA), Alisporivir (ALI), and H (CycH). We determine a series of conformers required for robust diffusion those relevant to other functions, such as binding protein targets or intermediates, presence solvent additives. investigate conformational interconversions establish correlations with permeability. Nuclear magnetic resonance (NMR) cyclic ion-mobility spectrometry-mass spectrometry (cIMS-MS) are employed characterize heterogeneity identify cis-amides good In addition, ion mobility selected cIMS-MS infrared (IR) multiple-photon dissociation (IRMPD) spectroscopy experiments conducted evaluate energy barriers between conformations. observe that CycA ALI, both cyclosporines favorable permeabilities, display multiple stable well-defined conformers. contrast, CycH, an epimer limited permeability, exhibits fewer demonstrate essential role shift from aqueous cis MeVal11–MeBmt1 state (A1) closed conformation featuring MeLeu9–MeLeu10 (C1) facilitating permeation. Additionally, we highlight transition A1 all-trans open (O1) is specifically triggered by CaCl2. also capture set Sar3–MeLeu4, MeLeu9–MeLeu10, denoted I. Conformationally IRMPD data [CycA+Ca]2+ show immediate repopulation original population distribution, suggesting CaCl2 smooths out barriers. Finally, our work presents improved sampling molecular dynamics approach based on refined force field not only consistently accurately captures established but strong predictive capabilities novel