Self-polymerization of archaeal RadA protein into long and fine helical filaments

Ming Hui Lee, Chih Hsiang Leng, Yuan Chih Chang, Chia Cheng Chou, Yi Kai Chen, Fu Fei Hsu, Chia Seng Chang, Andrew H.J. Wang, Ting Fang Wang

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


The Archaeal protein RadA, a RecA/Rad51 homolog, is able to promote pairing and exchange of DNA strands with homologous sequences. Here, we have expressed, purified, and crystallized the catalytically active RadA protein from Sulfolobus solfataricus (Sso). Preliminary X-ray analysis indicated that Sso RadA protein likely forms helical filament in protein crystals. Using atomic force microscopy with a carbon nanotube (CNT) tip for high-resolution imaging, we demonstrated that Sso RadA protein indeed forms fine helical filaments up to 1 μm in length (∼10 nm pitch) in the absence of DNA and nucleotide cofactor. We also observed that Sso RadA protein helical filament could dissemble upon incubation with ssDNA, and then the proteins associate with ssDNA to form nucleoprotein filament.

Original languageEnglish
Pages (from-to)845-851
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number3
Publication statusPublished - Oct 22 2004
Externally publishedYes


  • AFM
  • Dmc1
  • Homologous recombination
  • Rad51
  • RadA
  • RecA

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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