7RON

Crystal structure of the Friedel-Crafts alkylating enzyme CylK from Cylindospermum licheniforme

7RON の概要

• エントリーDOI: 10.2210/pdb7ron/pdb
• 分子名称: CylK, 1,2-ETHANEDIOL, CALCIUM ION, ... (6 entities in total)
• 機能のキーワード: beta-propeller, beta-roll, calcium-dependent, alkylation, cylindrocyclophane, transferase
• 由来する生物種: Cylindrospermum licheniforme UTEX B 2014
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 75905.72

構造登録者

Ruskoski, T.B.,Boal, A.K. (登録日: 2021-07-31, 公開日: 2022-03-23, 最終更新日: 2024-05-22)

主引用文献

Braffman, N.R.,Ruskoski, T.B.,Davis, K.M.,Glasser, N.R.,Johnson, C.,Okafor, C.D.,Boal, A.K.,Balskus, E.P.
Structural basis for an unprecedented enzymatic alkylation in cylindrocyclophane biosynthesis.
Elife, 11:-, 2022

PubMed Abstract: The cyanobacterial enzyme CylK assembles the cylindrocyclophane natural products by performing two unusual alkylation reactions, forming new carbon-carbon bonds between aromatic rings and secondary alkyl halide substrates. This transformation is unprecedented in biology, and the structure and mechanism of CylK are unknown. Here, we report X-ray crystal structures of CylK, revealing a distinctive fusion of a Ca-binding domain and a β-propeller fold. We use a mutagenic screening approach to locate CylK's active site at its domain interface, identifying two residues, Arg105 and Tyr473, that are required for catalysis. Anomalous diffraction datasets collected with bound bromide ions, a product analog, suggest that these residues interact with the alkyl halide electrophile. Additional mutagenesis and molecular dynamics simulations implicate Asp440 in activating the nucleophilic aromatic ring. Bioinformatic analysis of CylK homologs from other cyanobacteria establishes that they conserve these key catalytic amino acids, but they are likely associated with divergent reactivity and altered secondary metabolism. By gaining a molecular understanding of this unusual biosynthetic transformation, this work fills a gap in our understanding of how alkyl halides are activated and used by enzymes as biosynthetic intermediates, informing enzyme engineering, catalyst design, and natural product discovery.

PubMed: 35212625
DOI: 10.7554/eLife.75761

実験手法

X-RAY DIFFRACTION (1.68 Å)