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-Structure paper
タイトル | Visualization of two architectures in class-II CAP-dependent transcription activation. |
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ジャーナル・号・ページ | PLoS Biol, Vol. 18, Issue 4, Page e3000706, Year 2020 |
掲載日 | 2020年4月20日 |
![]() | Wei Shi / Yanan Jiang / Yibin Deng / Zigang Dong / Bin Liu / ![]() ![]() |
PubMed 要旨 | Transcription activation by cyclic AMP (cAMP) receptor protein (CAP) is the classic paradigm of transcription regulation in bacteria. CAP was suggested to activate transcription on class-II promoters ...Transcription activation by cyclic AMP (cAMP) receptor protein (CAP) is the classic paradigm of transcription regulation in bacteria. CAP was suggested to activate transcription on class-II promoters via a recruitment and isomerization mechanism. However, whether and how it modifies RNA polymerase (RNAP) to initiate transcription remains unclear. Here, we report cryo-electron microscopy (cryo-EM) structures of an intact Escherichia coli class-II CAP-dependent transcription activation complex (CAP-TAC) with and without de novo RNA transcript. The structures reveal two distinct architectures of TAC and raise the possibility that CAP binding may induce substantial conformational changes in all the subunits of RNAP and transiently widen the main cleft of RNAP to facilitate DNA promoter entering and formation of the initiation open complex. These structural changes vanish during further RNA transcript synthesis. The observations in this study may reveal a possible on-pathway intermediate and suggest a possibility that CAP activates transcription by inducing intermediate state, in addition to the previously proposed stabilization mechanism. |
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手法 | EM (単粒子) |
解像度 | 4.29 - 4.52 Å |
構造データ | EMDB-20286, PDB-6pb4: EMDB-20287, PDB-6pb5: EMDB-20288, PDB-6pb6: |
化合物 | ![]() ChemComp-ZN: ![]() ChemComp-MG: ![]() ChemComp-CMP: |
由来 |
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![]() | TRANSCRIPTION/DNA/RNA / class-II / transcription activation complex / CAP-dependent / de novo RNA synthesis / TRANSCRIPTION / TRANSCRIPTION-DNA-RNA complex / TRANSCRIPTION/DNA / TRANSCRIPTION-DNA complex / state 2 architecture |