6LRH
Crystal Structure of the Binary Complex of AgrE C264A mutant with L-arginine
Summary for 6LRH
| Entry DOI | 10.2210/pdb6lrh/pdb |
| Descriptor | Alr4995 protein, ARGININE (3 entities in total) |
| Functional Keywords | arginine dihydrolase, bifunctional enzyme, gme family, hydrolase |
| Biological source | Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576) |
| Total number of polymer chains | 2 |
| Total formula weight | 156420.73 |
| Authors | |
| Primary citation | Lee, H.,Rhee, S. Structural and mutational analyses of the bifunctional arginine dihydrolase and ornithine cyclodeaminase AgrE from the cyanobacteriumAnabaena. J.Biol.Chem., 295:5751-5760, 2020 Cited by PubMed Abstract: In cyanobacteria, metabolic pathways that use the nitrogen-rich amino acid arginine play a pivotal role in nitrogen storage and mobilization. The N-terminal domains of two recently identified bacterial enzymes: ArgZ from and AgrE from , have been found to contain an arginine dihydrolase. This enzyme provides catabolic activity that converts arginine to ornithine, resulting in concomitant release of CO and ammonia. In , the ArgZ-mediated ornithine-ammonia cycle plays a central role in nitrogen storage and remobilization. The C-terminal domain of AgrE contains an ornithine cyclodeaminase responsible for the formation of proline from ornithine and ammonia production, indicating that AgrE is a bifunctional enzyme catalyzing two sequential reactions in arginine catabolism. Here, the crystal structures of AgrE in three different ligation states revealed that it has a tetrameric conformation, possesses a binding site for the arginine dihydrolase substrate l-arginine and product l-ornithine, and contains a binding site for the coenzyme NAD(H) required for ornithine cyclodeaminase activity. Structure-function analyses indicated that the structure and catalytic mechanism of arginine dihydrolase in AgrE are highly homologous with those of a known bacterial arginine hydrolase. We found that in addition to other active-site residues, Asn-71 is essential for AgrE's dihydrolase activity. Further analysis suggested the presence of a passage for substrate channeling between the two distinct AgrE active sites, which are situated ∼45 Å apart. These results provide structural and functional insights into the bifunctional arginine dihydrolase-ornithine cyclodeaminase enzyme AgrE required for arginine catabolism in . PubMed: 32198136DOI: 10.1074/jbc.RA120.012768 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (2.70510472826 Å) |
Structure validation
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