2F23:
reference: pH-dependent conformational switch activates the inhibitor of transcription elongation., Laptenko O, Kim SS, Lee J, Starodubtseva M, Cava F, Berenguer J, Kong XP, Borukhov S, EMBO J. 2006 May 17;25(10):2131-41. Epub 2006 Apr 20. PMID: 16628221

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