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Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase.

Publication ,  Journal Article
Klemm, BP; Singh, D; Smith, CE; Hsu, AL; Dillard, LB; Krahn, JM; London, RE; Mueller, GA; Borgnia, MJ; Schaaper, RM
Published in: Proc Natl Acad Sci U S A
September 13, 2022

Levels of the cellular dNTPs, the direct precursors for DNA synthesis, are important for DNA replication fidelity, cell cycle control, and resistance against viruses. Escherichia coli encodes a dGTPase (2'-deoxyguanosine-5'-triphosphate [dGTP] triphosphohydrolase [dGTPase]; dgt gene, Dgt) that establishes the normal dGTP level required for accurate DNA replication but also plays a role in protecting E. coli against bacteriophage T7 infection by limiting the dGTP required for viral DNA replication. T7 counteracts Dgt using an inhibitor, the gene 1.2 product (Gp1.2). This interaction is a useful model system for studying the ongoing evolutionary virus/host "arms race." We determined the structure of Gp1.2 by NMR spectroscopy and solved high-resolution cryo-electron microscopy structures of the Dgt-Gp1.2 complex also including either dGTP substrate or GTP coinhibitor bound in the active site. These structures reveal the mechanism by which Gp1.2 inhibits Dgt and indicate that Gp1.2 preferentially binds the GTP-bound form of Dgt. Biochemical assays reveal that the two inhibitors use different modes of inhibition and bind to Dgt in combination to yield enhanced inhibition. We thus propose an in vivo inhibition model wherein the Dgt-Gp1.2 complex equilibrates with GTP to fully inactivate Dgt, limiting dGTP hydrolysis and preserving the dGTP pool for viral DNA replication.

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Published In

Proc Natl Acad Sci U S A

DOI

EISSN

1091-6490

Publication Date

September 13, 2022

Volume

119

Issue

37

Start / End Page

e2123092119

Location

United States

Related Subject Headings

  • Virus Replication
  • Viral Proteins
  • Protein Conformation
  • Guanosine Triphosphate
  • GTP Phosphohydrolases
  • Escherichia coli Proteins
  • Escherichia coli
  • DNA, Viral
  • DNA Replication
  • Cryoelectron Microscopy
 

Citation

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Chicago
ICMJE
MLA
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Klemm, B. P., Singh, D., Smith, C. E., Hsu, A. L., Dillard, L. B., Krahn, J. M., … Schaaper, R. M. (2022). Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase. Proc Natl Acad Sci U S A, 119(37), e2123092119. https://doi.org/10.1073/pnas.2123092119
Klemm, Bradley P., Deepa Singh, Cassandra E. Smith, Allen L. Hsu, Lucas B. Dillard, Juno M. Krahn, Robert E. London, Geoffrey A. Mueller, Mario J. Borgnia, and Roel M. Schaaper. “Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase.Proc Natl Acad Sci U S A 119, no. 37 (September 13, 2022): e2123092119. https://doi.org/10.1073/pnas.2123092119.
Klemm BP, Singh D, Smith CE, Hsu AL, Dillard LB, Krahn JM, et al. Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase. Proc Natl Acad Sci U S A. 2022 Sep 13;119(37):e2123092119.
Klemm, Bradley P., et al. “Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase.Proc Natl Acad Sci U S A, vol. 119, no. 37, Sept. 2022, p. e2123092119. Pubmed, doi:10.1073/pnas.2123092119.
Klemm BP, Singh D, Smith CE, Hsu AL, Dillard LB, Krahn JM, London RE, Mueller GA, Borgnia MJ, Schaaper RM. Mechanism by which T7 bacteriophage protein Gp1.2 inhibits Escherichia coli dGTPase. Proc Natl Acad Sci U S A. 2022 Sep 13;119(37):e2123092119.

Published In

Proc Natl Acad Sci U S A

DOI

EISSN

1091-6490

Publication Date

September 13, 2022

Volume

119

Issue

37

Start / End Page

e2123092119

Location

United States

Related Subject Headings

  • Virus Replication
  • Viral Proteins
  • Protein Conformation
  • Guanosine Triphosphate
  • GTP Phosphohydrolases
  • Escherichia coli Proteins
  • Escherichia coli
  • DNA, Viral
  • DNA Replication
  • Cryoelectron Microscopy