6JCY:
reference: Structures and mechanism of transcription initiation by bacterial ECF factors., Fang C, Li L, Shen L, Shi J, Wang S, Feng Y, Zhang Y, Nucleic Acids Res. 2019 May 27. pii: 5498757. doi: 10.1093/nar/gkz470. PMID: 31131408

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