title: Isolation of soluble scFv antibody fragments specific for small biomarker molecule, L-Carnitine, using phage display.
abstract: Isolation of single chain antibody fragment (scFv) clones from naïve Tomlinson I+J phage display libraries that specifically bind a small biomarker molecule, L-Carnitine, was performed using iterative affinity selection procedures. L-Carnitine has been described as a conditionally essential nutrient for humans. Abnormally high concentrations of L-Carnitine in urine are related to many health disorders including diabetes mellitus type 2 and lung cancer. ELISA-based affinity characterization results indicate that selectants preferentially bind to L-Carnitine in the presence of key bioselecting component materials and closely related L-Carnitine derivatives. In addition, the affinity results were confirmed using biophysical fluorescence quenching for tyrosine residues in the V segment. Small-scale production of the soluble fragment yielded 1.3mg/L using immunopure-immobilized protein A affinity column. Circular Dichroism data revealed that the antibody fragment (Ab) represents a folded protein that mainly consists of β-sheets. These novel antibody fragments may find utility as molecular affinity interface receptors in various electrochemical biosensor platforms to provide specific L-Carnitine binding capability with potential applications in metabolomic devices for companion diagnostics and personalized medicine applications. It may also be used in any other biomedical application where detection of the L-Carnitine level is important.
authors.affiliation: Department of Biological Sciences, University of Alberta, CCIS 5-012, Edmonton, AB T6G 2E1, Canada; Genetic Engineering and Biotechnology Research Institute, City of Scientific Research and Technological Applications, 21934 New-Burgelarab City, Alexandria, Egypt. Electronic address: rahmed@ualberta.ca.
authors.forename: Rabab M
authors.initials: RM
authors.lastname: Abou El-Magd
authors.affiliation: Department of Biological Sciences, University of Alberta, CCIS 5-012, Edmonton, AB T6G 2E1, Canada. Electronic address: vozza@ualberta.ca.
authors.forename: Nicolas F
authors.initials: NF
authors.lastname: Vozza
authors.affiliation: Experimental Oncology, Department of Oncology, University of Alberta, Canada; Cross Cancer Institute, 11560 University Avenue, Edmonton, AB T6G 1Z2, Canada; Department of Physics, University of Alberta, Edmonton, AB, Canada. Electronic address: jackt@ualberta.ca.
authors.forename: Jack A
authors.initials: JA
authors.lastname: Tuszynski
authors.affiliation: Department of Biological Sciences, University of Alberta, CCIS 5-012, Edmonton, AB T6G 2E1, Canada; Department of Computing Sciences, University of Alberta, Edmonton, AB T6G 2E8, Canada. Electronic address: dwishart@ualberta.ca.
authors.forename: David S
authors.initials: DS
authors.lastname: Wishart
mesh_terms: D000937:Antigen-Antibody Reactions; D015415:Biomarkers / Q000032:analysis; D002331:Carnitine / Q000032:analysis* / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D019151:Peptide Library; D057127:Single-Chain Antibodies / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000302:isolation & purification*; D012995:Solubility
chemical_list: D015415:Biomarkers; D019151:Peptide Library; D057127:Single-Chain Antibodies; D002331:Carnitine
keywords: Circular Dichroism (CD); Enzyme-linked immunosorbent assay (ELISA); Fluorescence quenching assay; L-Carnitine; Phage display; Single chain antibody fragment (scFv)