Structural basis for RNA recognition by NusB and NusE in the initiation of transcription antitermination.
Stagno, Jason R. 1; Altieri, Amanda S. 2; Bubunenko, Mikhail 3,4; Tarasov, Sergey G. 2; Li, Jess 2; Court, Donald L. 3; Byrd, R. Andrew 2; Ji, Xinhua 1,*
[Miscellaneous Article] Nucleic Acids Research. 39(17):7803-7815, September 2011.

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Processive transcription antitermination requires the assembly of the complete antitermination complex, which is initiated by the formation of the ternary NusB-NusE-BoxA RNA complex. We have elucidated the crystal structure of this complex, demonstrating that the BoxA RNA is composed of 8 nt that are recognized by the NusB-NusE heterodimer. Functional biologic and biophysical data support the structural observations and establish the relative significance of key protein-protein and protein-RNA interactions. Further crystallographic investigation of a NusB-NusE-dsRNA complex reveals a heretofore unobserved dsRNA binding site contiguous with the BoxA binding site. We propose that the observed dsRNA represents BoxB RNA, as both single-stranded BoxA and double-stranded BoxB components are present in the classical lambda antitermination site. Combining these data with known interactions amongst antitermination factors suggests a specific model for the assembly of the complete antitermination complex.

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