PDBsum entry 5fon

Ligase

PDB id: 5fon

Contents

Protein chains

281 a.a.

267 a.a.

Waters ×71

PDB id:

5fon

Name:

Ligase

Title:

Crystal structure of the cryptosporidium muris cytosolic leucyl-tRNA synthetase editing domain (apo structure)

Structure:

Leucyl-tRNA synthetase. Chain: a, c, d. Fragment: editing domain. Engineered: yes. Leucyl-tRNA synthetase. Chain: b. Fragment: editing domain. Engineered: yes

Source:

Cryptosporidium muris. Organism_taxid: 441375. Strain: rn66. Expressed in: escherichia coli. Expression_system_taxid: 469008. Expression_system_variant: ril.

Resolution:

2.70Å R-factor: 0.206 R-free: 0.256

Authors:

A.Palencia,R.J.Liu,M.Lukarska,J.Gut,A.Bougdour,B.Touquet,E.D.Wang, M.R.K.Alley,P.J.Rosenthal,M.A.Hakimi,S.Cusack

Key ref:

A.Palencia et al. (2016). Cryptosporidium and Toxoplasma Parasites Are Inhibited by a Benzoxaborole Targeting Leucyl-tRNA Synthetase. Antimicrob Agents Chemother, 60, 5817-5827. PubMed id: 27431220 DOI: 10.1128/AAC.00873-16

Date:

24-Nov-15 Release date: 03-Aug-16

Protein chain

B6AA20  (B6AA20_CRYMR) -  leucine--tRNA ligase from Cryptosporidium muris (strain RN66)

Seq: 1128 a.a.

Struc: 281 a.a.

Protein chains

B6AA20  (B6AA20_CRYMR) -  leucine--tRNA ligase from Cryptosporidium muris (strain RN66)

Seq: 1128 a.a.

Struc: 267 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: Chains A, B, C, D: E.C.6.1.1.4 - leucine--tRNA ligase.
• Reaction: tRNA(Leu) + L-leucine + ATP = L-leucyl-tRNA(Leu) + AMP + diphosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

reference

DOI no: 10.1128/AAC.00873-16

Antimicrob Agents Chemother 60:5817-5827 (2016)

PubMed id: 27431220

Cryptosporidium and Toxoplasma Parasites Are Inhibited by a Benzoxaborole Targeting Leucyl-tRNA Synthetase.

A.Palencia, R.J.Liu, M.Lukarska, J.Gut, A.Bougdour, B.Touquet, E.D.Wang, X.Li, M.R.Alley, Y.R.Freund, P.J.Rosenthal, M.A.Hakimi, S.Cusack.

ABSTRACT

The apicomplexan parasites Cryptosporidium and Toxoplasma are serious threats to human health. Cryptosporidiosis is a severe diarrheal disease in malnourished children and immunocompromised individuals, with the only FDA-approved drug treatment currently being nitazoxanide. The existing therapies for toxoplasmosis, an important pathology in immunocompromised individuals and pregnant women, also have serious limitations. With the aim of developing alternative therapeutic options to address these health problems, we tested a number of benzoxaboroles, boron-containing compounds shown to be active against various infectious agents, for inhibition of the growth of Cryptosporidium parasites in mammalian cells. A 3-aminomethyl benzoxaborole, AN6426, with activity in the micromolar range and with activity comparable to that of nitazoxanide, was identified and further characterized using biophysical measurements of affinity and crystal structures of complexes with the editing domain of Cryptosporidium leucyl-tRNA synthetase (LeuRS). The same compound was shown to be active against Toxoplasma parasites, with the activity being enhanced in the presence of norvaline, an amino acid that can be mischarged by LeuRS. Our observations are consistent with AN6426 inhibiting protein synthesis in both Cryptosporidium and Toxoplasma by forming a covalent adduct with tRNA(Leu) in the LeuRS editing active site and suggest that further exploitation of the benzoxaborole scaffold is a valid strategy to develop novel, much needed antiparasitic agents.