Related Experiment Video
Updated: Mar 12, 2026

Quantification of the Immunosuppressant Tacrolimus on Dried Blood Spots Using LC-MS/MS
Published on: November 8, 2015
Thioxylated cyclosporin A for studying protein-drug interactions
Weilin Lin1, Frank Erdmann2, Andres Quintero1
1B CUBE Center for Molecular Bioengineering, Technical University Dresden, Arnoldstr. 18, 01307 Dresden, Germany.
Abstract:
Single atom substitution of cyclosporin A (CsA) through thioxylation has been used to study the structure-activity relationship of the immunosuppressive complex, involving the CsA receptor protein cyclophilin 18 (Cyp18) and the immunological target protein phosphatase calcineurin (CaN), illustrating the contributions of peptide backbone in protein-drug interaction. Moreover, the subtle difference between thioxylation positions in CsA has led to a remarkable change in the quenching effect on Cyp18 intrinsic fluorescence. Using the thioxylated compound Cs7 as an isosteric derivative of CsA in competition assay, the experiment has led to the determination of koff value in solution. Whereas the conformational heterogeneity of CsA has been found to be associated with its two-phase binding kinetics to Cyp18, the dissociation rate of CsA from complex is independent from the initial ligand structure.
More Related Videos
08:49Identification of Mediators of T-cell Receptor Signaling via the Screening of Chemical Inhibitor Libraries
Published on: January 22, 2019
14:43Microfluidic On-chip Capture-cycloaddition Reaction to Reversibly Immobilize Small Molecules or Multi-component Structures for Biosensor Applications
Published on: September 23, 2013
Related Concept Videos
Factors Affecting Protein-Drug Binding: Drug Interactions
Displacement interactions can have varying outcomes, ranging from toxicity to virtually...
Drug toxicity: Drug–Drug Interaction
Pharmacokinetics: Drug–Drug Interactions
Pharmacokinetics: Drug–Food and Drug–Viral Interactions
Protein-Drug Binding: Mechanism and Kinetics
Various forces drive these interactions, including hydrogen bonds, hydrophobic interactions, ionic bonds, electrostatic interactions, and van der Waals forces. These bonds enable drugs to bind to specific sites on proteins,...
Hepatic Drug Clearance: Effect of Protein Binding
For low-extraction-ratio drugs that are less than 80% protein-bound, minor changes in protein binding...