Selection and characterization of peptide memitopes binding to ricin.
A combinatorial random peptide display library expressed in E. coli was employed to identify short, linear peptide sequences that showed affinity for ricin and could be used as reagents for detection and identification of ricin. One peptide, P3, from a collection of four short peptides showed specific binding to ricin. The kinetic analysis of this peptide binding to the ricin showed lower equilibrium binding constants for the peptide P3 than monoclonal antibody. This is attributed due to both slower association and faster dissociation rates for the peptide P3. The random ricin peptide P3 binds to ricin with a KD of 1 microM versus the antibody's KD of 14 nM. This particular peptide memitope P3 against ricin showed specific binding to ricin without any significant cross-reactivity against other proteins such as bovine serum albumin (BSA), lysozyme and natural bacterial toxins such as Staphylococcal enterotoxins A and B. The results provided proof-of-principal that peptide memitopes are another choice of reagents due to ease in production to be used for the detection of highly toxic bio-threat or biowarfare agents such as ricin.
US Army Edgewood Chemical and Biological Center, Aberdeen Proving Ground, MD 21010, USA. akbar.khan1@us.army.mil
Akbar S
AS
Khan
Roy
R
Thompson
Cheng
C
Cao
James J
JJ
Valdes
D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000378:metabolism; D000937:Antigen-Antibody Reactions; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D003001:Cloning, Molecular; D003429:Cross Reactions; D018604:Epitope Mapping / Q000379:methods*; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007156:Immunologic Memory; D036341:Intercellular Signaling Peptides and Proteins; D019151:Peptide Library; D010455:Peptides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D040081:Protein Array Analysis / Q000379:methods*; D011485:Protein Binding; D025941:Protein Interaction Mapping / Q000379:methods; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D012276:Ricin / Q000737:chemistry / Q000378:metabolism*
D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D036341:Intercellular Signaling Peptides and Proteins; D019151:Peptide Library; D010455:Peptides; D011994:Recombinant Proteins; C485059:peptide P3; D012276:Ricin