The effect of N- or C-terminal alterations of the connector of bacteriophage phi29 DNA packaging motor on procapsid assembly, pRNA binding, and DNA packaging

Ying Cai, Feng Xiao, Peixuan Guo

Research output: Contribution to journalArticle

19 Scopus citations


Double-stranded DNA viruses package their genomes into procapsids via an ATP-driven nanomotor. This ingenious motor configuration has inspired the development of biomimetics in nanotechnology. Bacteriophage φ{symbol}29 DNA-packaging motor has been a popular tool in nanomedicine. To provide information for further motor modification, conjugation, labeling, and manufacturing, the connector protein gp10 of the φ{symbol}29 DNA packaging motor was truncated, mutated, and extended. A 25-residue deletion or a 14-residue extension at the C terminus of gp10 did not affect procapsid assembly. A 42-amino acid extension at the N terminus did not interfere with the procapsid assembly but significantly decreased the DNA-packaging efficiency. DNA-packaging activity was restored upon protease cleavage of the extended region. Replacing the N-terminal peptide containing arginine and lysine with a histidine-rich peptide did not affect procapsid assembly but completely inhibited the packaging RNA (pRNA) binding to the connector and hindered subsequent DNA packaging. These results indicate that (1) the N-terminal arginine-lysine residues play a critical role in pRNA binding but are not essential for procapsid assembly; (2) the connector core, but not the flexible N- or C-terminal domains, is responsible for signaling the procapsid assembly; (3) pRNA binds to the connector as a result of electrostatic interactions between the polyanionic nature of nucleic acids and the cationic side groups of the amino acids, similar to RNA binding to Tat or polyArg.

Original languageEnglish (US)
Pages (from-to)8-18
Number of pages11
JournalNanomedicine: Nanotechnology, Biology, and Medicine
Issue number1
StatePublished - Mar 1 2008



  • Connector
  • DNA packaging motor
  • Procapsid assembly
  • phi29

ASJC Scopus subject areas

  • Bioengineering
  • Medicine (miscellaneous)
  • Molecular Medicine
  • Biomedical Engineering
  • Materials Science(all)
  • Pharmaceutical Science

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