6sjy | pdb_00006sjy

Diaminobutyrate acetyltransferase EctA from Paenibacillus lautus in complex with its product ADABA

spinqualitylabelsall models 6sjy, resolution 2.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6sjy is a 3 chain structure with sequence from "bacillus_lautus"_batchelor_1919 "bacillus lautus" batchelor 1919. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: 9YT, GOL, TRS Gene: ectA, GYMC10_5665 ("Bacillus lautus" Batchelor 1919) Activity: Diaminobutyrate acetyltransferase, with EC number 2.3.1.178 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [D3EKC1_GEOS4] Catalyzes the acetylation of L-2,4-diaminobutyrate (DABA) to gamma-N-acetyl-alpha,gamma-diaminobutyric acid (ADABA) with acetyl coenzyme A.[ARBA:ARBA00003741][RuleBase:RU365045] Publication Abstract from PubMed Ectoine is a solute compatible with the physiologies of both prokaryotic and eukaryotic cells and is widely synthesized by bacteria as an osmotic stress protectant. Because it preserves functional attributes of proteins and macromolecular complexes, it is considered a chemical chaperone and has found numerous practical applications. However, the mechanism of its biosynthesis is incompletely understood. The second step in ectoine biosynthesis is catalyzed by L-2,4-diaminobutyrate acetyltransferase (EctA; EC 2.3.1.178), which transfers the acetyl group from acetyl CoA to EctB-formed L-2,4-diaminobutyrate (DAB), yielding N-gamma-acetyl-L-2,4-diaminobutyrate (N-gamma-ADABA), the substrate of ectoine synthase (EctC). Here, we report the biochemical and structural characterization of the EctA enzyme from the thermotolerant bacterium Paenibacillus lautus (Pl). We found that (Pl)EctA forms a homodimer whose enzyme activity is highly regiospecific by producing N-gamma-ADABA but not the ectoine catabolic intermediate N-alpha-ADABA. High-resolution crystal structures of (Pl)EctA (at 1.2-2.2 A resolution) for (i) its apo form, (ii) in complex with CoA, (iii) in complex with DAB, (iv) in complex with both with CoA and DAB, and (v) in the presence of the product N-gamma-ADABA were obtained. To pinpoint residues involved in DAB binding, we probed the structure-function relationship of (Pl)EctA by site-directed mutagenesis. Phylogenomics shows that EctA-type proteins from both Bacteria and Archaea are evolutionarily highly conserved, including catalytically important residues. Collectively, our biochemical and structural findings yielded detailed insights into the catalytic core of the EctA enzyme that laid the foundation for unraveling its reaction mechanism. The architecture of the diaminobutyrate acetyltransferase active site provides mechanistic insight into the biosynthesis of the chemical chaperone ectoine.,Richter AA, Kobus S, Czech L, Hoeppner A, Zarzycki J, Erb TJ, Lauterbach L, Dickschat JS, Bremer E, Smits SHJ J Biol Chem. 2020 Jan 22. pii: RA119.011277. doi: 10.1074/jbc.RA119.011277. PMID:31969391 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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