National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
NIH GM131832
米国
引用
ジャーナル: Nat Commun / 年: 2024 タイトル: Structural basis for substrate binding and selection by human mitochondrial RNA polymerase. 著者: Karl Herbine / Ashok R Nayak / Dmitry Temiakov / 要旨: The mechanism by which RNAP selects cognate substrates and discriminates between deoxy and ribonucleotides is of fundamental importance to the fidelity of transcription. Here, we present cryo-EM ...The mechanism by which RNAP selects cognate substrates and discriminates between deoxy and ribonucleotides is of fundamental importance to the fidelity of transcription. Here, we present cryo-EM structures of human mitochondrial transcription elongation complexes that reveal substrate ATP bound in Entry and Insertion Sites. In the Entry Site, the substrate binds along the O helix of the fingers domain of mtRNAP but does not interact with the templating DNA base. Interactions between RNAP and the triphosphate moiety of the NTP in the Entry Site ensure discrimination against nucleosides and their diphosphate and monophosphate derivatives but not against non-cognate rNTPs and dNTPs. Closing of the fingers domain over the catalytic site results in delivery of both the templating DNA base and the substrate into the Insertion Site and recruitment of the catalytic magnesium ions. The cryo-EM data also reveal a conformation adopted by mtRNAP to reject a non-cognate substrate from its active site. Our findings establish a structural basis for substrate binding and suggest a unified mechanism of NTP selection for single-subunit RNAPs.
超分子 #1: Substrate ATP Bound to Insertion Site (IS) of Human Mitochondrial...
超分子
名称: Substrate ATP Bound to Insertion Site (IS) of Human Mitochondrial Transcription Elongation Complex タイプ: complex / ID: 1 / 親要素: 0 / 含まれる分子: #1-#5 詳細: Human Mitochondrial RNA polymerase (d119) and Human TEFM (d135) assembled on an RNA-DNA Scaffold in presence of methylene a,b-ATP
モデルのタイプ: OTHER / 詳細: Ab-initio reconstruction in cryoSPARC
最終 再構成
使用したクラス数: 1 / 想定した対称性 - 点群: C1 (非対称) / アルゴリズム: FOURIER SPACE / 解像度のタイプ: BY AUTHOR / 解像度: 2.74 Å / 解像度の算出法: FSC 0.143 CUT-OFF 詳細: Non-uniform Refinement (CryoSPARC) which is an algorithm based on cross-validation optimization, which automatically regularizes 3D density maps during refinement to account for spatial variability. 使用した粒子像数: 331858