Three-dimensional structural alignment based discovery and molecular basis of AtoB, catalyzing linear tetracyclic formation.
Ma, K., Liu, J., Huang, Z., Wu, M., Liu, D., Ren, J., Fan, A., Lin, W.(2024) Chem Sci 15: 18490-18496
- PubMed: 39430940 
- DOI: https://doi.org/10.1039/d4sc05590j
- Primary Citation of Related Structures:  
8ZEC, 8ZED, 9JLM - PubMed Abstract: 
Enzymes from the nuclear transport factor 2-like (NTF2-like) superfamily represent a rare group of biocatalysts with diverse catalytic functions facilitating intriguing skeleton formations. However, most proteins of this family remain enigmatic and await further elucidation. In this study, a combination of protein structural alignment with clustering analysis uncovers a new aldolase, AtoB, belonging to the NTF2-like superfamily. AtoB catalyzes the key intramolecular aldol reaction in linear tetracyclic meroterpenoid biosynthesis. The X-ray crystal structures of AtoB and AtoB-ligand complex are established at 1.9 Å and 1.6 Å resolution, respectively, revealing the rotation of the α4 helix and key residues in the active site for substrate binding. Molecular docking and site-directed mutagenesis demonstrate an acid-base pair involved in the AtoB-catalyzed aldol reaction, of which Arg59 is responsible for stereocontrol of hydroxylated C-10a during condensation. These findings provide valuable information for understanding the catalytic mechanisms of the AtoB-catalyzed aldol reaction. Additionally, a branching biosynthetic pathway of aspertetranones is elucidated during the exploration of the natural substrate of AtoB.
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Beijing 100191 China fanaili@bjmu.edu.cn whlin@bjmu.edu.cn.
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