N protein from lambdoid phages transforms NusA into an antiterminator by modulating NusA-RNA polymerase flap domain interactions

Mishra, Saurabh ; Sen, Ranjan (2015) N protein from lambdoid phages transforms NusA into an antiterminator by modulating NusA-RNA polymerase flap domain interactions Nucleic Acids Research, 43 (12). pp. 5744-5758. ISSN 0305-1048

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Official URL: https://academic.oup.com/nar/article/43/12/5744/29...

Related URL: http://dx.doi.org/10.1093/nar/gkv479

Abstract

Interaction of the lambdoid phage N protein with the bacterial transcription elongation factor NusA is the key component in the process of transcription antitermination. A convex surface of E. coli NusA-NTD, located opposite to its RNA polymerase-binding domain (the β-flap domain), directly interacts with N in the antitermination complex. We hypothesized that this N-NusA interaction induces allosteric effects on the NusA-RNAP interaction leading to transformation of NusA into a facilitator of the antitermination process. Here we showed that mutations in β-flap domain specifically defective for N antitermination exhibited altered NusA-nascent RNA interaction and have widened RNA exit channel indicating an intricate role of flap domain in the antitermination. The presence of N reoriented the RNAP binding surface of NusA-NTD, which changed its interaction pattern with the flap domain. These changes caused significant spatial rearrangement of the β-flap as well as the β′ dock domains to form a more constricted RNA exit channel in the N-modified Elongation Complex (EC), which might play key role in converting NusA into a facilitator of the N antitermination. We propose that in addition to affecting the RNA exit channel and the active center of the EC, β-flap domain rearrangement is also a mechanistic component in the N antitermination process.

Item Type:Article
Source:Copyright of this article belongs to Oxford University Press.
ID Code:114746
Deposited On:04 Jun 2018 05:51
Last Modified:04 Jun 2018 05:51

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