Cyclosporin Peptide Derivatives Reveal How Conformation Controls Membrane Permeability | Research

The takeaway

Study of cyclosporin O derivatives revealed how intramolecular hydrogen bonds and conformational "chameleonicity" control membrane permeability and cyclophilin A binding, informing oral macrocyclic peptide drug design.

Chameleonicity is key
Peptides that change shape between water and membrane environments (chameleonicity) achieve the best oral permeability — a design principle for macrocyclic drugs

What the researchers found

Cyclosporin O derivatives demonstrated that intramolecular hydrogen bonds and conformational chameleonicity determine membrane permeability and cyclophilin A binding. Conformation-permeability-binding relationships were mapped with PK profiling.

Why it matters

Oral delivery of macrocyclic peptides is a major pharmaceutical goal. Understanding the conformational rules that govern membrane permeability enables rational design of orally bioavailable peptide drugs for currently undruggable targets.

The numbers in context

CsO F=12% oral bioavailability; minimal CypA binding; higher plasma concentration than CsA; less chameleonic in polar media

How the study worked

Structure-property study. Cyclosporin O and derivatives CP1-3. Conformational analysis. Membrane permeability assessment. Cyclophilin A binding. Pharmacokinetic profiling. Intramolecular hydrogen bond characterization.

Who was studied

ICR mice (PK); Caco-2 cells (permeability); NMR structural analysis

What this study cannot tell us

Limited to cyclosporin O scaffold. Rules may not generalize to all macrocyclic peptides. PK profiling scope not detailed. Cell-based permeability may not match in vivo absorption.

How to read the evidence

Moderate evidence: systematic structure-property study with multiple derivatives, permeability data, and PK profiling.

When this study was published

Published 2021. Macrocyclic peptide oral delivery is an active pharmaceutical design area.

The bigger picture

Chameleonicity — the ability of a peptide to change its properties with its environment — is emerging as the key design principle for orally available macrocyclic drugs. This study provides concrete examples and design rules.

Questions still open

Can chameleonicity be computationally predicted during macrocycle design?
Do these conformation-permeability rules apply to non-cyclosporin macrocycles?
Could artificial chameleonicity be engineered into otherwise impermeable peptides?

Common questions

What is chameleonicity in peptides?

Just like a chameleon changes color, some peptides change their shape depending on environment. In water, they expose their polar groups. In a fatty cell membrane, they hide these groups internally. This shape-shifting ability allows them to cross membranes and be absorbed orally.

Why is this important for making peptide pills?

Most peptide drugs must be injected because they can't cross the gut membrane. Understanding the structural features that enable membrane crossing (like chameleonicity) allows chemists to design peptides that can be taken as pills — dramatically improving patient convenience.

Read the original research

Interplay among Conformation, Intramolecular Hydrogen Bonds, and Chameleonicity in the Membrane Permeability and Cyclophilin A Binding of Macrocyclic Peptide Cyclosporin O Derivatives.

Journal of medicinal chemistry, 64(12), 8272-8286

View on PubMed ↗Publisher’s paper ↗

Citation

Lee, Dongjae; Lee, Sungjin; Choi, Jieun; Song, Yoo-Kyung; Kim, Min Ju; Shin, Dae-Seop; Bae, Myung Ae; Kim, Yong-Chul; Park, Chin-Ju; Lee, Kyeong-Ryoon; Choi, Jun-Ho; Seo, Jiwon. (2021). Interplay among Conformation, Intramolecular Hydrogen Bonds, and Chameleonicity in the Membrane Permeability and Cyclophilin A Binding of Macrocyclic Peptide Cyclosporin O Derivatives.. Journal of medicinal chemistry, 64(12), 8272-8286. https://doi.org/10.1021/acs.jmedchem.1c00211