6SLL

Diaminobutyrate acetyltransferase EctA from Paenibacillus lautus in complex with its substrate L-2,4-diaminobutyric acid (DAB) and coenzyme A

6SLL の概要

• エントリーDOI: 10.2210/pdb6sll/pdb
• 分子名称: L-2,4-diaminobutyric acid acetyltransferase, COENZYME A, 2,4-DIAMINOBUTYRIC ACID, ... (5 entities in total)
• 機能のキーワード: l-2, 4-diaminobutyrate acetyltransferase, acetyl coenzyme a, acetylation, stress response, chemical chaperone, transferase
• 由来する生物種: Geobacillus sp. (strain Y412MC10)
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 43450.44

構造登録者

Richter, A.A.,Kobus, S.,Czech, L.,Hoeppner, A.,Bremer, E.,Smits, S.H.J. (登録日: 2019-08-20, 公開日: 2020-01-29, 最終更新日: 2024-01-24)

主引用文献

Richter, A.A.,Kobus, S.,Czech, L.,Hoeppner, A.,Zarzycki, J.,Erb, T.J.,Lauterbach, L.,Dickschat, J.S.,Bremer, E.,Smits, S.H.J.
The architecture of the diaminobutyrate acetyltransferase active site provides mechanistic insight into the biosynthesis of the chemical chaperone ectoine.
J.Biol.Chem., 295:2822-2838, 2020

PubMed Abstract: 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 -γ-acetyl-l-2,4-diaminobutyrate (-γ-ADABA), the substrate of ectoine synthase (EctC). Here, we report the biochemical and structural characterization of the EctA enzyme from the thermotolerant bacterium (). We found that ()EctA forms a homodimer whose enzyme activity is highly regiospecific by producing -γ-ADABA but not the ectoine catabolic intermediate -α-acetyl-l-2,4-diaminobutyric acid. High-resolution crystal structures of ()EctA (at 1.2-2.2 Å resolution) (i) for its apo-form, (ii) in complex with CoA, (iii) in complex with DAB, (iv) in complex with both CoA and DAB, and (v) in the presence of the product -γ-ADABA were obtained. To pinpoint residues involved in DAB binding, we probed the structure-function relationship of ()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.

PubMed: 31969391
DOI: 10.1074/jbc.RA119.011277

実験手法

X-RAY DIFFRACTION (1.2 Å)