ジャーナル: Nat Commun / 年: 2025 タイトル: Cryo-EM Structure of the relaxosome, a complex essential for bacterial mating and the spread of antibiotic resistance genes. 著者: Sunanda M Williams / Sandra Raffl / Sabine Kienesberger / Aravindan Ilangovan / Ellen L Zechner / Gabriel Waksman / 要旨: Bacterial mating, or conjugation, was discovered nearly 80 years ago as a process transferring genes from one bacterial cell (the donor) to another (the recipient). It requires three key multiprotein ...Bacterial mating, or conjugation, was discovered nearly 80 years ago as a process transferring genes from one bacterial cell (the donor) to another (the recipient). It requires three key multiprotein complexes in the donor cell: a DNA-processing machinery called the relaxosome, a double-membrane spanning type 4 secretion system (T4SS), and an extracellular appendage termed pilus. While the near-atomic resolution structures of the T4SS and pilus are already known, that of the relaxosome has not been reported to date. Here, we describe the cryo-EM structure of the fully assembled relaxosome encoded by the paradigm F plasmid in two different states corresponding to distinct functional steps along the DNA processing reaction. By varying the structures of model DNAs we delineate conformational changes required to initiate conjugation. Mutational studies of the various protein-protein and protein-DNA interaction hubs suggest a complex sensitive to trigger signals, that could arise from cell-to-cell contacts with recipient cells.
解像度のタイプ: BY AUTHOR / 解像度: 6.5 Å / 解像度の算出法: FSC 0.143 CUT-OFF 詳細: A reconstruction resulting from initial processing of the cryoEM dataset to yield a low resolution map showing order/disorder in the trans-esterase (TE) domain of TraI. In this initial 3D map ...詳細: A reconstruction resulting from initial processing of the cryoEM dataset to yield a low resolution map showing order/disorder in the trans-esterase (TE) domain of TraI. In this initial 3D map of the relaxosome, TE domain is disordered as the oriT DNA (ss-27_-13ds-12_+143) used was not conducive to dsDNA melting. 使用した粒子像数: 338844
初期 角度割当
タイプ: MAXIMUM LIKELIHOOD / 詳細: CryoSPARC ab-initio
最終 角度割当
タイプ: MAXIMUM LIKELIHOOD / 詳細: Homogeneous refinement