6S3E

Crystal structure of helicase Pif1 from Thermus oshimai in apo form

6S3E の概要

• エントリーDOI: 10.2210/pdb6s3e/pdb
• 分子名称: PIF1 helicase (1 entity in total)
• 機能のキーワード: dna helicase, hydrolase
• 由来する生物種: Thermus oshimai JL-2
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 100881.63

構造登録者

Dai, Y.X.,Chen, W.F.,Teng, F.Y.,Liu, N.N.,Hou, X.M.,Dou, S.X.,Rety, S.,Xi, X.G. (登録日: 2019-06-25, 公開日: 2021-01-13, 最終更新日: 2024-01-24)

主引用文献

Dai, Y.X.,Chen, W.F.,Liu, N.N.,Teng, F.Y.,Guo, H.L.,Hou, X.M.,Dou, S.X.,Rety, S.,Xi, X.G.
Structural and functional studies of SF1B Pif1 from Thermus oshimai reveal dimerization-induced helicase inhibition.
Nucleic Acids Res., 49:4129-4143, 2021

PubMed Abstract: Pif1 is an SF1B helicase that is evolutionarily conserved from bacteria to humans and plays multiple roles in maintaining genome stability in both nucleus and mitochondria. Though highly conserved, Pif1 family harbors a large mechanistic diversity. Here, we report crystal structures of Thermus oshimai Pif1 (ToPif1) alone and complexed with partial duplex or single-stranded DNA. In the apo state and in complex with a partial duplex DNA, ToPif1 is monomeric with its domain 2B/loop3 adopting a closed and an open conformation, respectively. When complexed with a single-stranded DNA, ToPif1 forms a stable dimer with domain 2B/loop3 shifting to a more open conformation. Single-molecule and biochemical assays show that domain 2B/loop3 switches repetitively between the closed and open conformations when a ToPif1 monomer unwinds DNA and, in contrast with other typical dimeric SF1A helicases, dimerization has an inhibitory effect on its helicase activity. This mechanism is not general for all Pif1 helicases but illustrates the diversity of regulation mechanisms among different helicases. It also raises the possibility that although dimerization results in activation for SF1A helicases, it may lead to inhibition for some of the other uncharacterized SF1B helicases, an interesting subject warranting further studies.

PubMed: 33784404
DOI: 10.1093/nar/gkab188

実験手法

X-RAY DIFFRACTION (3.787 Å)