5HJA: Crystal structure of Leishmania mexicana arginase in complex with inhibitor ABHDP

Citation:
Abstract
Leishmania arginase is a potential drug target for the treatment of leishmaniasis because this binuclear manganese metalloenzyme initiates de novo polyamine biosynthesis by catalyzing the hydrolysis of L-arginine to generate L-ornithine and urea. The product L-ornithine subsequently undergoes decarboxylation to yield putrescine, which in turn is utilized for spermidine biosynthesis. Polyamines such as spermidine are essential for the growth and survival of the parasite, so inhibition of enzymes in the polyamine-biosynthetic pathway comprises an effective strategy for treating parasitic infections. To this end, two X-ray crystal structures of L. mexicana arginase complexed with alpha,alpha-disubstituted boronic amino-acid inhibitors based on the molecular scaffold of 2-(S)-amino-6-boronohexanoic acid are now reported. Structural comparisons with human and parasitic arginase complexes reveal interesting differences in the binding modes of the additional alpha-substituents, i.e. the D side chains, of these inhibitors. Subtle differences in the three-dimensional contours of the outer active-site rims among arginases from different species lead to different conformations of the D side chains and thus different inhibitor-affinity trends. The structures suggest that it is possible to maintain affinity while fine-tuning intermolecular interactions of the D side chain of alpha,alpha-disubstituted boronic amino-acid inhibitors in the search for isozyme-specific and species-specific arginase inhibitors.
PDB ID: 5HJADownload
MMDB ID: 138408
PDB Deposition Date: 2016/1/13
Updated in MMDB: 2017/09
Experimental Method:
x-ray diffraction
Resolution: 1.65  Å
Source Organism:
Similar Structures:
Biological Unit for 5HJA: trimeric; determined by author and by software (PISA)
Molecular Components in 5HJA
Label Count Molecule
Proteins (3 molecules)
3
Arginase
Molecule annotation
Chemicals (12 molecules)
1
6
2
3
3
3
* Click molecule labels to explore molecular sequence information.

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