Peptides panned from a phage-displayed random peptide library are useful for the detection of Bacillus anthracis surrogates B. cereus 4342 and B. anthracis Sterne.
Recent use of Bacillus anthracis as a bioweapon has highlighted the need for a sensitive monitoring system. Current bacterial detection tests use antibodies as bio-molecular recognition elements which have limitations with regard to time, specificity and sensitivity, creating the need for new and improved cost-effective high-affinity detection probes. In this study, we screened a commercially available bacteriophage-displayed random peptide library using Bacillus cereus 4342 cells as bait to identify peptides that could be used for detection of Bacillus. The method enabled us to identify two 12-amino acid consensus peptide sequences that specifically bind to B. cereus 4342 and B. anthracis Sterne, the nonpathogenic surrogates of B. anthracis strain. The two Bacillus-binding peptides (named BBP-1 and BBP-2) were synthesized with biotin tag to confirm their binding by four independent detection assays. Dot-blot analysis revealed that the peptides bind specifically to B. cereus 4342 and B. anthracis Sterne. Quantitative analysis of this interaction by ELISA and fluorometry demonstrated a detection sensitivity of 10(2) colony forming U/ml (CFU/ml) by both assays. When the peptides were used in combination with Qdots, the sensitivity was enhanced further by enabling detection of even a single bacterium by fluorescence microscopy. Immunoblot analysis and protein sequencing showed that BBP-1 and BBP-2 bound to the S-layer protein of B. anthracis Sterne. Overall, our findings validate the usefulness of synthetic versions of phage-derived peptides in combination with Qdot-liquid nanocrystals as high sensitivity bioprobes for various microbial detection platforms.
Sainath Rao
Shilpakala
S
Section of Cell Biology, Laboratory of Cellular Hematology, Center for Biologics Evaluation and Research, FDA, Bethesda, MD 20892, USA.
Mohan
Ketha V K
KV
Nguyen
Nga
N
Abraham
Bindu
B
Abdouleva
Galina
G
Zhang
Pei
P
Atreya
Chintamani D
CD
D000595:Amino Acid Sequence; D001408:Bacillus anthracis / Q000737:chemistry / Q000302:isolation & purification*; D001409:Bacillus cereus / Q000737:chemistry / Q000302:isolation & purification*; D001694:Biological Warfare; D001710:Biotin / Q000737:chemistry; D004784:Environmental Monitoring; D004797:Enzyme-Linked Immunosorbent Assay; D008856:Microscopy, Fluorescence; D019151:Peptide Library; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000235:genetics
D019151:Peptide Library; D010455:Peptides; D001710:Biotin