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bioRxiv · 10.1101/2022.10.14.512049

The structural basis for the self-inhibition of DNA binding by apo-σ70

Joron, K.·Zamel, J.·Dvir, S.·Kalisman, N.·Lerner, E.
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Abstract

The initiation of transcription in Escherichia coli (E. coli) is facilitated by promoter specificity factors, also known as {sigma} factors, which may bind a promoter only as part of a complex with RNA polymerase (RNAP). By performing in vitro cross-linking mass spectrometry (CL-MS) of apo-{sigma}70, we reveal structural features suggesting a compact conformation compared to the known RNAP-bound extended conformation. Then, we validate the existence of the compact conformation using in vivo CL-MS by identifying cross-links similar to those found in vitro, which deviate from the extended conformation only during the stationary phase of bacterial growth. Conclusively, we provide information in support of a compact conformation of apo-{sigma}70 that exists in live cells, which might represent a transcriptionally-inactive form that can be activated upon binding to RNAP.

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Joron, K., Zamel, J., Dvir, S., Kalisman, N., Lerner, E.. 2022-10-15. The structural basis for the self-inhibition of DNA binding by apo-σ70. https://doi.org/10.1101/2022.10.14.512049

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