T7 phage factor required for managing RpoS inEscherichia coli.
Tabib-Salazar, A., Liu, B., Barker, D., Burchell, L., Qimron, U., Matthews, S.J., Wigneshweraraj, S.(2018) Proc Natl Acad Sci U S A 115: E5353-E5362
- PubMed: 29789383 
- DOI: https://doi.org/10.1073/pnas.1800429115
- Primary Citation of Related Structures:  
6FI7 - PubMed Abstract: 
T7 development in Escherichia coli requires the inhibition of the housekeeping form of the bacterial RNA polymerase (RNAP), Eσ 70 , by two T7 proteins: Gp2 and Gp5.7. Although the biological role of Gp2 is well understood, that of Gp5.7 remains to be fully deciphered. Here, we present results from functional and structural analyses to reveal that Gp5.7 primarily serves to inhibit Eσ S , the predominant form of the RNAP in the stationary phase of growth, which accumulates in exponentially growing E. coli as a consequence of the buildup of guanosine pentaphosphate [(p)ppGpp] during T7 development. We further demonstrate a requirement of Gp5.7 for T7 development in E. coli cells in the stationary phase of growth. Our finding represents a paradigm for how some lytic phages have evolved distinct mechanisms to inhibit the bacterial transcription machinery to facilitate phage development in bacteria in the exponential and stationary phases of growth.
Organizational Affiliation: 
Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, SW7 2AZ London, United Kingdom.