9YI9

Cryo-EM structure of yeast Mgm101 in the lock-washer apo state

9YI9 の概要

• エントリーDOI: 10.2210/pdb9yi9/pdb
• EMDBエントリー: 72983
• 分子名称: Mitochondrial genome maintenance protein MGM101 (1 entity in total)
• 機能のキーワード: single strand annealing protein, ssap, annealase, dna binding protein
• 由来する生物種: Saccharomyces cerevisiae (brewer's yeast)
• タンパク質・核酸の鎖数: 18
• 化学式量合計: 513441.63

構造登録者

Wheat, C.T.,Bell, C.E. (登録日: 2025-10-01, 公開日: 2025-11-05, 最終更新日: 2025-12-10)

主引用文献

Wheat, C.T.,Qi, Z.,Hussain, M.,Zakharova, K.,Wysocki, V.H.,Bell, C.E.
Mechanism of single-strand annealing from native mass spectrometry and cryo-EM structures of RAD52 homolog Mgm101.
Biorxiv, 2025

PubMed Abstract: RAD52, the primary single-strand annealing (SSA) protein in humans, forms undecameric rings that bind ssDNA within a narrow, positively-charged groove. Whether RAD52 anneals two complementary ssDNAs on the same ring in , or between two ring-ssDNA complexes in , is unknown. Here, we determined cryo-EM structures of Mgm101, a RAD52 homolog from yeast mitochondria, in complexes with ssDNA, a duplex intermediate of annealing, and B-form dsDNA product. In all states, Mgm101 forms a closed nonadecameric ring that binds the backbone of the first ssDNA at the base of the narrow groove. The second complementary strand binds directly on top of the first to form an extended, unwound, and circular duplex intermediate of annealing. The third complex captures apparent B-form DNA product bound to a novel β-hairpin motif located on top of the Mgm101 ring, above the primary DNA-binding groove. Mass photometry and native mass spectrometry confirm and further elucidate the complexes formed in solution. Altogether, our data reveal the full SSA pathway of Mgm101 and suggest it anneals two complementary ssDNAs on the same ring in . Structural conservation with RAD52 suggests it is likely to use a similar mechanism of annealing.

PubMed: 41280126
DOI: 10.1101/2025.10.26.684629

実験手法

ELECTRON MICROSCOPY (2.96 Å)