TY  - JOUR
A1  - Klein, Philipp
A1  - Johe, Patrick
A1  - Wagner, Annika
A1  - Jung, Sascha
A1  - Kühlborn, Jonas
A1  - Barthels, Fabian
A1  - Tenzer, Stefan
A1  - Distler, Ute
A1  - Waigel, Waldemar
A1  - Engels, Bernd
A1  - Hellmich, Ute A.
A1  - Opatz, Till
A1  - Schirmeister, Tanja
T1  - New cysteine protease inhibitors: electrophilic (het)arenes and unexpected prodrug identification for the Trypanosoma protease rhodesain
JF  - Molecules
N2  - Electrophilic (het)arenes can undergo reactions with nucleophiles yielding π- or Meisenheimer (σ-) complexes or the products of the S\(_N\)Ar addition/elimination reactions. Such building blocks have only rarely been employed for the design of enzyme inhibitors. Herein, we demonstrate the combination of a peptidic recognition sequence with such electrophilic (het)arenes to generate highly active inhibitors of disease-relevant proteases. We further elucidate an unexpected mode of action for the trypanosomal protease rhodesain using NMR spectroscopy and mass spectrometry, enzyme kinetics and various types of simulations. After hydrolysis of an ester function in the recognition sequence of a weakly active prodrug inhibitor, the liberated carboxylic acid represents a highly potent inhibitor of rhodesain (K\(_i\) = 4.0 nM). The simulations indicate that, after the cleavage of the ester, the carboxylic acid leaves the active site and re-binds to the enzyme in an orientation that allows the formation of a very stable π-complex between the catalytic dyad (Cys-25/His-162) of rhodesain and the electrophilic aromatic moiety. The reversible inhibition mode results because the S\(_N\)Ar reaction, which is found in an alkaline solvent containing a low molecular weight thiol, is hindered within the enzyme due to the presence of the positively charged imidazolium ring of His-162. Comparisons between measured and calculated NMR shifts support this interpretation
KW  - cysteine protease
KW  - rhodesain
KW  - electrophilic (het)arene
KW  - nucleophilic aromatic substitution
KW  - Meisenheimer complex
KW  - π-complex
KW  - prodrug
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-203380
SN  - 1420-3049
VL  - 25
IS  - 6
ER  -