Affordable Access

deepdyve-link
Publisher Website

HNH proteins are a widespread component of phage DNA packaging machines.

Authors
  • Kala, Smriti
  • Cumby, Nichole
  • Sadowski, Paul D
  • Hyder, Batool Zafar
  • Kanelis, Voula
  • Davidson, Alan R
  • Maxwell, Karen L
Type
Published Article
Journal
Proceedings of the National Academy of Sciences
Publisher
Proceedings of the National Academy of Sciences
Publication Date
Apr 22, 2014
Volume
111
Issue
16
Pages
6022–6027
Identifiers
DOI: 10.1073/pnas.1320952111
PMID: 24711378
Source
Medline
Keywords
License
Unknown

Abstract

The genome packaging reactions of tailed bacteriophages and herpes viruses require the activity of a terminase enzyme, which is comprised of large and small subunits. Phage genomes are replicated as linear concatemers composed of multiple copies of the genome joined end to end. As the terminase enzyme packages the genome into the phage capsid, it cleaves the DNA into single genome-length units. In this work, we show that the phage HK97 HNH protein, gp74, is required for the specific endonuclease activity of HK97 terminase and is essential for phage head morphogenesis. HNH proteins are a very common family of proteins generally associated with nuclease activity that are found in all kingdoms of life. We show that the activity of gp74 in terminase-mediated cleavage of the phage cos site relies on the presence of an HNH motif active-site residue, and that the large subunit of HK97 terminase physically interacts with gp74. Bioinformatic analysis reveals that the role of HNH proteins in terminase function is widespread among long-tailed phages and is uniquely required for the activity of the Terminase_1 family of large terminase proteins.

Report this publication

Statistics

Seen <100 times