National Institutes of Health/National Human Genome Research Institute (NIH/NHGRI)
米国
引用
ジャーナル: Nat Commun / 年: 2020 タイトル: Structural asymmetry governs the assembly and GTPase activity of McrBC restriction complexes. 著者: Yiming Niu / Hiroshi Suzuki / Christopher J Hosford / Thomas Walz / Joshua S Chappie / 要旨: 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 ...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.
分子量: 539.246 Da / 分子数: 4 / 由来タイプ: 合成 / 式: C10H16N5O13P3S / タイプ: SUBJECT OF INVESTIGATION
研究の焦点であるリガンドがあるか
Y
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実験情報
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実験
実験
手法: X線回折 / 使用した結晶の数: 1
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試料調製
結晶
マシュー密度: 2.14 Å3/Da / 溶媒含有率: 42.54 %
結晶化
温度: 298 K / 手法: 蒸気拡散法, シッティングドロップ法 / pH: 6.5 詳細: 0.1M sodium acetate, pH 6.5, 17.5 % MPD with a drop size of 2 micro-liters and reservoir volume of 650 micro-liters.