9MG2

Structure of Kluyveromyces lactis mRNA cap (guanine-N7) methyltransferase, Abd1, in complex with sinefungin

9MG2 の概要

• エントリーDOI: 10.2210/pdb9mg2/pdb
• 関連するPDBエントリー: 9MG0 9MG1 9MG3
• 分子名称: mRNA cap guanine-N(7) methyltransferase, SINEFUNGIN, 1,2-ETHANEDIOL, ... (6 entities in total)
• 機能のキーワード: methyltransferase, mrna, cap, sinefungin, transferase, abd1, k. lactis
• 由来する生物種: Kluyveromyces lactis NRRL Y-1140
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 67979.01

構造登録者

Nilson, D.J.,Fedorov, E.,Ghosh, A. (登録日: 2024-12-10, 公開日: 2025-07-09, 最終更新日: 2025-08-06)

主引用文献

Nilson, D.J.,Schwer, B.,Almo, S.C.,Shuman, S.,Ghosh, A.
Structural basis for sensitivity and acquired resistance of fungal cap guanine-N7 methyltransferases to the antifungal antibiotic sinefungin.
Nucleic Acids Res., 53:-, 2025

PubMed Abstract: The essential enzyme messenger RNA (mRNA) (guanine-N7) methyltransferase catalyzes S-adenosylmethionine (SAM)-dependent conversion of GpppRNA ends to the m7GpppRNA cap structure characteristic of eukaryal mRNAs. The antibiotic sinefungin (SFG) is a SAM analog in which the S-CH3 sulfonium moiety of SAM is replaced by a C-NH2 amine. Available evidence indicates that the antifungal activity of SFG is exerted via inhibition of fungal cap methyltransferase Abd1. Here we report that recombinant Kluyveromyces lactis and Saccharomyces cerevisiae Abd1 are 240-fold and 485-fold more sensitive to inhibition by SFG than by the reaction product S-adenosylhomocysteine (SAH). Crystal structures of K. lactis and S. cerevisiae Abd1 as binary complexes with SAH or SFG and ternary complexes with GTP•SFG highlight how SFG makes two hydrogen bonds from its C-NH2 amine to the guanine-O6 and -N7 atoms of GTP that account for its higher affinity vis-à-vis SAH and SAM. Through a genetic screen to isolate SFG-resistant S. cerevisiae strains, a conserved tyrosine (Tyr416) that interacts with the cap guanine in Abd1 was identified as a key determinant of SFG potency. Tyr416 Abd1 variants confer SFG resistance in vitro by weakening cap-assisted SFG interactions with Abd1. Our study illuminates the basis for the exquisite SFG sensitivity of fungal cap methyltransferases.

PubMed: 40682821
DOI: 10.1093/nar/gkaf538

実験手法

X-RAY DIFFRACTION (1.59 Å)