Rational design of aziridine-containing cysteine protease inhibitors with improved potency: Studies on inhibition mechanism

Abstract

AbstractTo enable a rational design of improved cysteine protease inhibitors, the present work investigates trends in the inhibition potency of aziridine derivatives with a substituted nitrogen center. To predict the influence of electron‐withdrawing substituents, quantum chemical computations of the ring opening of N‐formylated, N‐methylated, and N‐unsubstituted aziridines with thiolate were performed. They revealed that the N‐formyl group leads to a strong decrease of the reaction barrier and a considerable increase in exothermicity due to stabilization of the transition state. In contrast, a nucleophilic attack at the carbonyl carbon atom is characterized by very low reaction barriers, suggesting a reversible reaction, thus providing the theoretical background for the reversible inhibition of cysteine proteases by peptidyl aldehydes. Reactions of aziridine building blocks (diethyl aziridine‐2,3‐dicarboxylate 1, diethyl 1‐formyl aziridine‐2,3‐dicarboxylate 2) with a model thiolate in aqueous solution which were followed by NMR spectroscopy and mass spectrometry, showed the N‐formylated compound 2 to readily undergo a ring‐opening reaction. In contrast, the reaction of 1 with the thiolate is much slower. Enzyme assays with the cysteine protease cathepsin L showed 2 to be a 5000‐fold better enzyme inhibitor than 1. Dialysis assays clearly proved irreversible inhibition. These experiments, together with the results obtained with the model thiolate, indicate that the main inhibition mechanism of the N‐formylated aziridine 2 is the ring‐opening reaction rather than the reversible attack of the active site cysteine residue at the carbonyl carbon atom.

Autoren

Radim Vicik
Holger Helten
Tanja Schirmeister
Bernd Engels

DOI

10.1002/cmdc.200600081

eISSN

1860-7187

ISSN

1860-7179

Ausgabe der Veröffentlichung

9

Zeitschrift

ChemMedChem

Sprache

en

Online publication date

2006

Paginierung

1021 - 1028

Datum der Veröffentlichung

2006

Status

Published

Herausgeber

Wiley

Herausgeber URL

http://dx.doi.org/10.1002/cmdc.200600081

Datum der Datenerfassung

2023

Titel

Rational Design of Aziridine‐Containing Cysteine Protease Inhibitors with Improved Potency: Studies on Inhibition Mechanism

Ausgabe der Zeitschrift

1

Data source: Crossref

Abstract

To enable a rational design of improved cysteine protease inhibitors, the present work investigates trends in the inhibition potency of aziridine derivatives with a substituted nitrogen center. To predict the influence of electron-withdrawing substituents, quantum chemical computations of the ring opening of N-formylated, N-methylated, and N-unsubstituted aziridines with thiolate were performed. They revealed that the N-formyl group leads to a strong decrease of the reaction barrier and a considerable increase in exothermicity due to stabilization of the transition state. In contrast, a nucleophilic attack at the carbonyl carbon atom is characterized by very low reaction barriers, suggesting a reversible reaction, thus providing the theoretical background for the reversible inhibition of cysteine proteases by peptidyl aldehydes. Reactions of aziridine building blocks (diethyl aziridine-2,3-dicarboxylate 1, diethyl 1-formyl aziridine-2,3-dicarboxylate 2) with a model thiolate in aqueous solution which were followed by NMR spectroscopy and mass spectrometry, showed the N-formylated compound 2 to readily undergo a ring-opening reaction. In contrast, the reaction of 1 with the thiolate is much slower. Enzyme assays with the cysteine protease cathepsin L showed 2 to be a 5000-fold better enzyme inhibitor than 1. Dialysis assays clearly proved irreversible inhibition. These experiments, together with the results obtained with the model thiolate, indicate that the main inhibition mechanism of the N-formylated aziridine 2 is the ring-opening reaction rather than the reversible attack of the active site cysteine residue at the carbonyl carbon atom.

Addresses

Institute of Pharmacy and Food Chemistry, University of Würzburg Am Hubland, 97074 Würzburg, Germany.

Autoren

Radim Vicik
Holger Helten
Tanja Schirmeister
Bernd Engels

DOI

10.1002/cmdc.200600081

eISSN

1860-7187

Externe Identifier

PubMed Identifier: 16933238

Open access

false

ISSN

1860-7179

Ausgabe der Veröffentlichung

9

Zeitschrift

ChemMedChem

Schlüsselwörter

Protons
Nitrogen
Dimethyl Sulfoxide
Aziridines
Cysteine Proteinase Inhibitors
Solvents
Dialysis
Magnetic Resonance Spectroscopy
Drug Design
Kinetics
Thermodynamics
Entropy

Sprache

eng

Medium

Print

Paginierung

1021 - 1028

Datum der Veröffentlichung

2006

Status

Published

Datum der Datenerfassung

2006

Titel

Rational design of aziridine-containing cysteine protease inhibitors with improved potency: studies on inhibition mechanism.

Sub types

Research Support, Non-U.S. Gov't
Journal Article

Ausgabe der Zeitschrift

1

Data source: Europe PubMed Central

Abstract

To enable a rational design of improved cysteine protease inhibitors, the present work investigates trends in the inhibition potency of aziridine derivatives with a substituted nitrogen center. To predict the influence of electron-withdrawing substituents, quantum chemical computations of the ring opening of N-formylated, N-methylated, and N-unsubstituted aziridines with thiolate were performed. They revealed that the N-formyl group leads to a strong decrease of the reaction barrier and a considerable increase in exothermicity due to stabilization of the transition state. In contrast, a nucleophilic attack at the carbonyl carbon atom is characterized by very low reaction barriers, suggesting a reversible reaction, thus providing the theoretical background for the reversible inhibition of cysteine proteases by peptidyl aldehydes. Reactions of aziridine building blocks (diethyl aziridine-2,3-dicarboxylate 1, diethyl 1-formyl aziridine-2,3-dicarboxylate 2) with a model thiolate in aqueous solution which were followed by NMR spectroscopy and mass spectrometry, showed the N-formylated compound 2 to readily undergo a ring-opening reaction. In contrast, the reaction of 1 with the thiolate is much slower. Enzyme assays with the cysteine protease cathepsin L showed 2 to be a 5000-fold better enzyme inhibitor than 1. Dialysis assays clearly proved irreversible inhibition. These experiments, together with the results obtained with the model thiolate, indicate that the main inhibition mechanism of the N-formylated aziridine 2 is the ring-opening reaction rather than the reversible attack of the active site cysteine residue at the carbonyl carbon atom.

Autoren

Radim Vicik
Holger Helten
Tanja Schirmeister
Bernd Engels

Autoren-URL

https://www.ncbi.nlm.nih.gov/pubmed/16933238

DOI

10.1002/cmdc.200600081

ISSN

1860-7179

Ausgabe der Veröffentlichung

9

Zeitschrift

ChemMedChem

Schlüsselwörter

Aziridines
Cysteine Proteinase Inhibitors
Dialysis
Dimethyl Sulfoxide
Drug Design
Entropy
Kinetics
Magnetic Resonance Spectroscopy
Nitrogen
Protons
Solvents
Thermodynamics

Sprache

eng

Country

Germany

Paginierung

1021 - 1028

Datum der Veröffentlichung

2006

Status

Published

Datum, an dem der Datensatz öffentlich gemacht wurde

2006

Titel

Rational design of aziridine-containing cysteine protease inhibitors with improved potency: studies on inhibition mechanism.

Sub types

Journal Article
Research Support, Non-U.S. Gov't

Ausgabe der Zeitschrift

1

Data source: PubMed

Rational design of aziridine-containing cysteine protease inhibitors with improved potency: Studies on inhibition mechanism

Tools