1rxx

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spinqualitylabelsall models 1rxx, resolution 2.45Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

Structure of arginine deiminase

Overview

l-Arginine deiminase (ADI) catalyzes the irreversible hydrolysis of, arginine to citrulline and ammonia. ADI is involved in the first step of, the most widespread anaerobic route of arginine degradation. ADI, missing, in high eukaryotes, is a potential antimicrobial and antiparasitic drug, target. We have determined the crystal structure of ADI from Pseudomonas, aeruginosa by the multi-wavelength anomalous diffraction method at 2.45 A, resolution. The structure exhibits similarity to other arginine-modifying, or substituted arginine-modifying enzymes such as dimethylarginine, dimethylaminohydrolase (DDAH), arginine:glycine amidinotransferase, and, arginine:inosamine-phosphate amidinotransferase, despite the lack of, significant amino acid sequence homology to these enzymes. The similarity, spans a core domain comprising five betabetaalphabeta motifs arranged in a, circle around a 5-fold pseudosymmetry axis. ADI contains an additional, alpha-helical domain of novel topology inserted between the first and the, second betabetaalphabeta modules. A catalytic triad, Cys-His-Glu/Asp, (arranged in a different manner from that of the thiol proteases), seen in, the other arginine-modifying enzymes is also conserved in ADI, as well as, many other residues involved in substrate binding. Based on this, conservation pattern and the assumption that the substrate binding mode is, similar to that of DDAH, an ADI catalytic mechanism is proposed. The main, players are Cys-406, which mounts the nucleophilic attack on the carbon, atom of the guanidinium group of arginine, and His-278, which serves as a, general base.

About this Structure

1RXX is a Single protein structure of sequence from Pseudomonas aeruginosa. Active as Arginine deiminase, with EC number 3.5.3.6 Full crystallographic information is available from OCA.

Reference

Structural insight into arginine degradation by arginine deiminase, an antibacterial and parasite drug target., Galkin A, Kulakova L, Sarikaya E, Lim K, Howard A, Herzberg O, J Biol Chem. 2004 Apr 2;279(14):14001-8. Epub 2003 Dec 30. PMID:14701825

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