Screening and characterization of high-affinity ssDNA aptamers against anthrax protective antigen

Ji Sun Choi, Sang Gon Kim, Mieke Lahousse, Hye Yeon Park, Hae Chul Park, Byeongmoon Jeong, Jinheung Kim, Sung Kun Kim, Moon Young Yoon

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


The protective antigen (PA) of Bacillus anthracis is a secreted protein that functions as a critical virulence factor. Protective antigen has been selected as a biomarker in detecting bacterial infection. The in vitro selection method, systematic evolution of ligands by exponential enrichment (SELEX), was used to find single-stranded DNAs that were tightly bound to PA. After 8 rounds of the SELEX process with PA, 4 different oligonucleotides (referred to as aptamers) that contain a 30-residue ssDNA sequence were identified. Dissociation constant (Kd) values with Cy3-attached aptamers were determined via fluorophotometry to be within a nanomolar range. The authors attempted to visualize the detection of PA using an aptamer-based enzyme-linked immunosorbent assay method, which has proven to be successful within a nanomolar K d value range. Furthermore, 2 of the 4 aptamers exhibited specificity to PA against bovine serum albumin and bovine serum. The results of this study demonstrate the analytical potential of an oligonucleotide-based biosensor for a wide variety of applications, particularly in diagnosing disease through specific protein biomarkers.

Original languageEnglish
Pages (from-to)266-271
Number of pages6
JournalJournal of Biomolecular Screening
Issue number2
StatePublished - Feb 2011


  • Bacillus anthracis
  • anthrax
  • aptamer
  • protective antigen


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