ジャーナル: Nucleic Acids Res / 年: 2014 タイトル: Organization of the human mitochondrial transcription initiation complex. 著者: Elena Yakubovskaya / Kip E Guja / Edward T Eng / Woo Suk Choi / Edison Mejia / Dmitri Beglov / Mark Lukin / Dima Kozakov / Miguel Garcia-Diaz / 要旨: Initiation of transcription in human mitochondria involves two factors, TFAM and TFB2M, in addition to the mitochondrial RNA polymerase, POLRMT. We have investigated the organization of the human ...Initiation of transcription in human mitochondria involves two factors, TFAM and TFB2M, in addition to the mitochondrial RNA polymerase, POLRMT. We have investigated the organization of the human mitochondrial transcription initiation complex on the light-strand promoter (LSP) through solution X-ray scattering, electron microscopy (EM) and biochemical studies. Our EM results demonstrate a compact organization of the initiation complex, suggesting that protein-protein interactions might help mediate initiation. We demonstrate that, in the absence of DNA, only POLRMT and TFAM form a stable interaction, albeit one with low affinity. This is consistent with the expected transient nature of the interactions necessary for initiation and implies that the promoter DNA acts as a scaffold that enables formation of the full initiation complex. Docking of known crystal structures into our EM maps results in a model for transcriptional initiation that strongly correlates with new and existing biochemical observations. Our results reveal the organization of TFAM, POLRMT and TFB2M around the LSP and represent the first structural characterization of the entire mitochondrial transcriptional initiation complex.
超分子 #1000: Quaternary complex of POLRMT, TFAM, TFB2M and LSP DNA
超分子
名称: Quaternary complex of POLRMT, TFAM, TFB2M and LSP DNA タイプ: sample / ID: 1000 詳細: The complex also has a DNA, that has a mitochondrial light strand promoter sequence 集合状態: one POLRMT one TFB2M and one TFAM TFAM) / Number unique components: 3
Reference free classes were divided into two subsets, based on particle size, and two initial models were generated from each subset. One model had a visibly elongated shape, whereas the other was more compact. We utilized both models as starting points for parallel refinement, as implemented in EMAN MULTIREFINE routine
CTF補正
詳細: EMAN2 protocol each particle
最終 再構成
想定した対称性 - 点群: C1 (非対称) / アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 25.0 Å / 解像度の算出法: OTHER / ソフトウェア - 名称: EMAN2 / 使用した粒子像数: 12453