6LRG

Crystal Structure of the Ternary Complex of AgrE with Ornithine and NAD+

6LRG の概要

• エントリーDOI: 10.2210/pdb6lrg/pdb
• 分子名称: Alr4995 protein, NICOTINAMIDE-ADENINE-DINUCLEOTIDE, L-ornithine, ... (4 entities in total)
• 機能のキーワード: arginine dihydrolase, bifunctional enzyme, gme family, hydrolase
• 由来する生物種: Nostoc sp. (strain PCC 7120 / SAG 25.82 / UTEX 2576)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 157062.18

構造登録者

Lee, H.,Rhee, S. (登録日: 2020-01-16, 公開日: 2020-04-01, 最終更新日: 2023-11-29)

主引用文献

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

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: 32198136
DOI: 10.1074/jbc.RA120.012768

実験手法

X-RAY DIFFRACTION (2.4121811586 Å)