National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
U54 AI150472
米国
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
R01 AI136680
米国
引用
ジャーナル: Nucleic Acids Res / 年: 2022 タイトル: B-to-A transition in target DNA during retroviral integration. 著者: Ilona K Jóźwik / Wen Li / Da-Wei Zhang / Doris Wong / Julia Grawenhoff / Allison Ballandras-Colas / Sriram Aiyer / Peter Cherepanov / Alan N Engelman / Dmitry Lyumkis / 要旨: Integration into host target DNA (tDNA), a hallmark of retroviral replication, is mediated by the intasome, a multimer of integrase (IN) assembled on viral DNA (vDNA) ends. To ascertain aspects of ...Integration into host target DNA (tDNA), a hallmark of retroviral replication, is mediated by the intasome, a multimer of integrase (IN) assembled on viral DNA (vDNA) ends. To ascertain aspects of tDNA recognition during integration, we have solved the 3.5 Å resolution cryo-EM structure of the mouse mammary tumor virus (MMTV) strand transfer complex (STC) intasome. The tDNA adopts an A-like conformation in the region encompassing the sites of vDNA joining, which exposes the sugar-phosphate backbone for IN-mediated strand transfer. Examination of existing retroviral STC structures revealed conservation of A-form tDNA in the analogous regions of these complexes. Furthermore, analyses of sequence preferences in genomic integration sites selectively targeted by six different retroviruses highlighted consistent propensity for A-philic sequences at the sites of vDNA joining. Our structure additionally revealed several novel MMTV IN-DNA interactions, as well as contacts seen in prior STC structures, including conserved Pro125 and Tyr149 residues interacting with tDNA. In infected cells, Pro125 substitutions impacted the global pattern of MMTV integration without significantly altering local base sequence preferences at vDNA insertion sites. Collectively, these data advance our understanding of retroviral intasome structure and function, as well as factors that influence patterns of vDNA integration in genomic DNA.
凍結剤: ETHANE / 装置: HOMEMADE PLUNGER 詳細: Cryo-EM grids were prepared by freezing using a manual plunger in cold room at 4C.
詳細
MMTV STC intasomes were applied onto R1.2/1.3 gold UltrAufoil grids, Au 300 mesh (Quantifoil). Cryo-EM grids were prepared by manually freezing using a manual plunger in cold room at 4C and stored in liquid nitrogen for future data acquisition.
アルゴリズム: FOURIER SPACE / 解像度のタイプ: BY AUTHOR / 解像度: 3.5 Å / 解像度の算出法: FSC 0.143 CUT-OFF / ソフトウェア - 名称: cryoSPARC (ver. 3.0) / 使用した粒子像数: 50196
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原子モデル構築 1
詳細
Initial model building was accomplished by rigid-body fitting of the MMTV CSC structure downloaded from the Protein Data Bank (PDB ID: 3JCA) into the EM map in Chimera 1.14 by Fit in Map tool. Unmodeled protein and DNA residues were manually built in Coot 0.9.4.1 and the structure underwent a few iterative cycles of manual model re-building and real-space refinement in Phenix. Ramachandran and secondary structure restraints were applied. To model the full octameric intasome, we additionally rigid-body docked the flanking IN dimers (PDB ID: 5CZ2) into the map. The density connecting the flanking dimers and the core was evident, but broken, and therefore a model was not derived for the linker regions. The final model accounts for the complete octameric MMTV STC intasome with connections for the linker regions.
精密化
空間: REAL / プロトコル: FLEXIBLE FIT / 当てはまり具合の基準: CC
得られたモデル
PDB-7usf: Mouse mammary tumor virus strand transfer complex intasome