8cq3 | pdb_00008cq3

Bifunctional chorismate mutase/cyclohexadienyl dehydratase from Aequoribacter fuscus

spinqualitylabelsall models 8cq3, resolution 1.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 8cq3 is a 1 chain structure with sequence from Aequoribacter fuscus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.55Å Ligands: ACT, CL Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function A0A7Z2NRM1_9GAMM Publication Abstract from PubMed Chorismate mutase (CM) and cyclohexadienyl dehydratase (CDT) catalyze two subsequent reactions in the intracellular biosynthesis of l-phenylalanine (Phe). Here, we report the discovery of novel and extremely rare bifunctional fusion enzymes, consisting of fused CM and CDT domains, which are exported from the cytoplasm. Such enzymes were found in only nine bacterial species belonging to non-pathogenic gamma- or beta-Proteobacteria. In gamma-proteobacterial fusion enzymes, the CM domain is N-terminal to the CDT domain, whereas in beta-Proteobacteria the order is inverted. The CM domains share 15-20% sequence identity with the AroQ(gamma) class CM holotype of Mycobacterium tuberculosis (*MtCM), and the CDT domains 40-60% identity with the exported monofunctional enzyme of Pseudomonas aeruginosa (PheC). In vitro kinetics revealed a K(m) <7 muM, much lower than for *MtCM, whereas kinetic parameters are similar for CDT domains and PheC. There is no feedback inhibition of CM or CDT by the pathway's end product Phe, and no catalytic benefit of the domain fusion compared to engineered single-domain constructs. The fusion enzymes of Aequoribacter fuscus, Janthinobacterium sp. HH01, and Duganella sacchari were crystallized and their structures refined to 1.6, 1.7, and 2.4 A resolution, respectively. Neither the crystal structures nor size-exclusion chromatography show evidence for substrate channeling or higher oligomeric structure that could account for cooperation of CM and CDT active sites. The genetic neighborhood with genes encoding transporter and substrate binding proteins suggests that these exported bifunctional fusion enzymes may participate in signaling systems rather than in the biosynthesis of Phe. Novel exported fusion enzymes with chorismate mutase and cyclohexadienyl dehydratase activity: shikimate pathway enzymes teamed up in no man's land.,Stocker C, Khatanbaatar T, Bressan L, Wurth-Roderer K, Cordara G, Krengel U, Kast P J Biol Chem. 2023 Aug 14:105161. doi: 10.1016/j.jbc.2023.105161. PMID:37586588 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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