1R1O: Amino Acid Sulfonamides As Transition-State Analogue Inhibitors Of Arginase

Citation:
Abstract
Arginase is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of L-arginine to form L-ornithine plus urea. Chiral L-amino acids bearing sulfonamide side chains have been synthesized in which the tetrahedral sulfonamide groups are designed to target bridging coordination interactions with the binuclear manganese cluster in the arginase active site. Syntheses of the amino acid sulfonamides have been accomplished by the amination of sulfonyl halide derivatives of (S)-(tert-butoxy)-[(tert-butoxycarbonyl)amino]oxoalkanoic acids. Amino acid sulfonamides with side chains comparable in length to that of L-arginine exhibit inhibition in the micromolar range, and the X-ray crystal structure of arginase I complexed with one of these inhibitors, S-(2-sulfonamidoethyl)-L-cysteine, has been determined at 2.8 A resolution. In the enzyme-inhibitor complex, the sulfonamide group displaces the metal-bridging hydroxide ion of the native enzyme and bridges the binuclear manganese cluster with an ionized NH(-) group. The binding mode of the sulfonamide inhibitor may mimic the binding of the tetrahedral intermediate and its flanking transition states in catalysis. It is notable that the ionized sulfonamide group is an excellent bridging ligand in this enzyme-inhibitor complex; accordingly, the sulfonamide functionality can be considered in the design of inhibitors targeting other binuclear metalloenzymes.
PDB ID: 1R1ODownload
MMDB ID: 25129
PDB Deposition Date: 2003/9/24
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 2.8  Å
Source Organism:
Similar Structures:
Biological Unit for 1R1O: trimeric; determined by author and by software (PISA)
Molecular Components in 1R1O
Label Count Molecule
Proteins (3 molecules)
3
Arginase 1(Gene symbol: Arg1)
Molecule annotation
Chemicals (9 molecules)
1
6
2
3
* Click molecule labels to explore molecular sequence information.

Citing MMDB
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