8S94

Structure of C-terminal domains of Walker B mutated MCM8/9 heterohexamer complex with ADP

8S94 の概要

• エントリーDOI: 10.2210/pdb8s94/pdb
• EMDBエントリー: 40234 40235 40236
• 分子名称: DNA helicase MCM8, DNA helicase MCM9, ADENOSINE-5'-DIPHOSPHATE, ... (4 entities in total)
• 機能のキーワード: dna replication, dna repair, dna binding protein
• 由来する生物種: Homo sapiens (human); 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 666618.93

構造登録者

Li, C.,Gao, Y. (登録日: 2023-03-27, 公開日: 2023-06-07, 最終更新日: 2023-08-23)

主引用文献

McKinzey, D.R.,Li, C.,Gao, Y.,Trakselis, M.A.
Activity, substrate preference and structure of the HsMCM8/9 helicase.
Nucleic Acids Res., 51:7330-7341, 2023

PubMed Abstract: The minichromosomal maintenance proteins, MCM8 and MCM9, are more recent evolutionary additions to the MCM family, only cooccurring in selected higher eukaryotes. Mutations in these genes are directly linked to ovarian insufficiency, infertility, and several cancers. MCM8/9 appears to have ancillary roles in fork progression and recombination of broken replication forks. However, the biochemical activity, specificities and structures have not been adequately illustrated, making mechanistic determination difficult. Here, we show that human MCM8/9 (HsMCM8/9) is an ATP dependent DNA helicase that unwinds fork DNA substrates with a 3'-5' polarity. High affinity ssDNA binding occurs in the presence of nucleoside triphosphates, while ATP hydrolysis weakens the interaction with DNA. The cryo-EM structure of the HsMCM8/9 heterohexamer was solved at 4.3 Å revealing a trimer of heterodimer configuration with two types of interfacial AAA+ nucleotide binding sites that become more organized upon binding ADP. Local refinements of the N or C-terminal domains (NTD or CTD) improved the resolution to 3.9 or 4.1 Å, respectively, and shows a large displacement in the CTD. Changes in AAA+ CTD upon nucleotide binding and a large swing between the NTD and CTD likely implies that MCM8/9 utilizes a sequential subunit translocation mechanism for DNA unwinding.

PubMed: 37309874
DOI: 10.1093/nar/gkad508

実験手法

ELECTRON MICROSCOPY (3.94 Å)