3vpc
ArgX from Sulfolobus tokodaii complexed with ADP
Structural highlights
FunctionARGX_SULTO Catalyzes the ATP-dependent formation of a covalent bond between the amino group of glutamate and the gamma-carboxyl group of the C-terminal glutamate residue in LysW (By similarity). Publication Abstract from PubMedLysW has been identified as a carrier protein in the lysine biosynthetic pathway that is active through the conversion of alpha-aminoadipate (AAA) to lysine. In this study, we found that the hyperthermophilic archaeon, Sulfolobus acidocaldarius, not only biosynthesizes lysine through LysW-mediated protection of AAA but also uses LysW to protect the amino group of glutamate in arginine biosynthesis. In this archaeon, after LysW modification, AAA and glutamate are converted to lysine and ornithine, respectively, by a single set of enzymes with dual functions. The crystal structure of ArgX, the enzyme responsible for modification and protection of the amino moiety of glutamate with LysW, was determined in complex with LysW. Structural comparison and enzymatic characterization using Sulfolobus LysX, Sulfolobus ArgX and Thermus LysX identify the amino acid motif responsible for substrate discrimination between AAA and glutamate. Phylogenetic analysis reveals that gene duplication events at different stages of evolution led to ArgX and LysX. Lysine and arginine biosyntheses mediated by a common carrier protein in Sulfolobus.,Ouchi T, Tomita T, Horie A, Yoshida A, Takahashi K, Nishida H, Lassak K, Taka H, Mineki R, Fujimura T, Kosono S, Nishiyama C, Masui R, Kuramitsu S, Albers SV, Kuzuyama T, Nishiyama M Nat Chem Biol. 2013 Apr;9(4):277-83. doi: 10.1038/nchembio.1200. Epub 2013 Feb, 24. PMID:23434852[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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