6UT3

X-ray structure of Thermococcus gammatolerans McrB AAA+ domain hexamer in P21 symmetry

6UT3 の概要

• エントリーDOI: 10.2210/pdb6ut3/pdb
• 分子名称: GTPase subunit of restriction endonuclease, MAGNESIUM ION, 5'-GUANOSINE-DIPHOSPHATE-MONOTHIOPHOSPHATE (3 entities in total)
• 機能のキーワード: aaa protein, gtpase, methylation-dependent restriction, dna binding protein
• 由来する生物種: Thermococcus gammatolerans (strain DSM 15229 / JCM 11827 / EJ3)
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 303077.52

構造登録者

Niu, Y.,Hosford, C.J.,Chappie, J.S. (登録日: 2019-10-29, 公開日: 2020-10-21, 最終更新日: 2024-03-06)

主引用文献

Niu, Y.,Suzuki, H.,Hosford, C.J.,Walz, T.,Chappie, J.S.
Structural asymmetry governs the assembly and GTPase activity of McrBC restriction complexes.
Nat Commun, 11:5907-5907, 2020

PubMed Abstract: McrBC complexes are motor-driven nucleases functioning in bacterial self-defense by cleaving foreign DNA. The GTP-specific AAA + protein McrB powers translocation along DNA and its hydrolysis activity is stimulated by its partner nuclease McrC. Here, we report cryo-EM structures of Thermococcus gammatolerans McrB and McrBC, and E. coli McrBC. The McrB hexamers, containing the necessary catalytic machinery for basal GTP hydrolysis, are intrinsically asymmetric. This asymmetry directs McrC binding so that it engages a single active site, where it then uses an arginine/lysine-mediated hydrogen-bonding network to reposition the asparagine in the McrB signature motif for optimal catalytic function. While the two McrBC complexes use different DNA-binding domains, these contribute to the same general GTP-recognition mechanism employed by all G proteins. Asymmetry also induces distinct inter-subunit interactions around the ring, suggesting a coordinated and directional GTP-hydrolysis cycle. Our data provide insights into the conserved molecular mechanisms governing McrB family AAA + motors.

PubMed: 33219217
DOI: 10.1038/s41467-020-19735-4

実験手法

X-RAY DIFFRACTION (2.95 Å)