Peptides designed from a bacteriophage capsid protein function as synthetic transcription repressors.

Autor: Sharma PV; Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India; Graduate Studies, Manipal Academy of Higher Education, Manipal, Karnataka, India., Jain S; Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India., Sen R; Laboratory of Transcription, Center for DNA Fingerprinting and Diagnostics, Hyderabad, India. Electronic address: rsen@cdfd.org.in.
Jazyk: angličtina
Zdroj: The Journal of biological chemistry [J Biol Chem] 2023 Dec; Vol. 299 (12), pp. 105373. Date of Electronic Publication: 2023 Oct 20.
DOI: 10.1016/j.jbc.2023.105373
Abstrakt: The bacteriophage capsid protein, Psu (polarity suppression), inhibits the bacterial transcription terminator, Rho. In an effort to find nontraditional antibacterial agents, we previously designed peptides from the Psu C terminus that function as inhibitors of Rho. Here, we demonstrated that these peptides have positive surface-charge densities, and they downregulate many genes in Escherichia coli. We hypothesized that these peptides could bind to nucleic acids and repress gene expression. One of these peptides, peptide 33, represses in vitro transcription from the T7A1 and P lac promoters efficiently by blocking the access of RNA polymerase to the promoter, a mode of transcription repression akin to many bacterial repressors. In vivo, expressions of the peptides reduce the total RNA level as well as transcription from P lac and P osm promoters significantly. However, they are less efficient in repressing transcription from the rRNA promoters with a very high turnover of RNA polymerase. The peptide 33 binds to both single and dsDNA as well as to RNA with dissociation constants ranging from 1 to 5 μM exhibiting preferences for the single-stranded DNA and RNAs. These interactions are salt-resistant and not sequence-specific. Interactions with dsDNA are entropy-driven, while it is enthalpy-driven for the ssDNA. This mode of interaction with nucleic acids is similar to many nonspecific ssDNA-binding proteins. Expression of peptide 33 induces cell elongation and impaired cell division, possibly due to the dislodging of the DNA-binding proteins. Overall, we surmised that these synthetic transcription repressors would function like bacterial nucleoid-associated proteins.
Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article.
(Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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