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Published March 2017 | Published + Supplemental Material
Journal Article Open

Protein Catalyzed Capture Agents with Tailored Performance for In Vitro and In Vivo Applications


We report on peptide-based ligands matured through the protein catalyzed capture (PCC) agent method to tailor molecular binders for in vitro sensing/diagnostics and in vivo pharmacokinetics parameters. A vascular endothelial growth factor (VEGF) binding peptide and a peptide against the protective antigen (PA) protein of Bacillus anthracis discovered through phage and bacterial display panning technologies, respectively, were modified with click handles and subjected to iterative in situ click chemistry screens using synthetic peptide libraries. Each azide-alkyne cycloaddition iteration, promoted by the respective target proteins, yielded improvements in metrics for the application of interest. The anti-VEGF PCC was explored as a stable in vivo imaging probe. It exhibited excellent stability against proteases and a mean elimination in vivo half-life (T_(1/2)) of 36 min. Intraperitoneal injection of the reagent results in slow clearance from the peritoneal cavity and kidney retention at extended times, while intravenous injection translates to rapid renal clearance. The ligand competed with the commercial antibody for binding to VEGF in vivo. The anti-PA ligand was developed for detection assays that perform in demanding physical environments. The matured anti-PA PCC exhibited no solution aggregation, no fragmentation when heated to 100°C, and  > 81% binding activity for PA after heating at 90°C for 1 h. We discuss the potential of the PCC agent screening process for the discovery and enrichment of next generation antibody alternatives.

Additional Information

© 2016 The Authors Peptide Science Published by Wiley Periodicals, Inc. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Issue online: 25 March 2017; Version of record online: 25 March 2017; Accepted manuscript online: 19 August 2016; The authors would like to thank Jonathan Bohn from Enzo Life Sciences for technical support and Yue Li of the University of Maryland Mass Spectrometry Facility for performing mass spectrometry confirmations. This research was primarily supported by the Army Institute for Collaborative Biotechnologies through grant W911NF-09-0001 and B.F. was supported by an HHMI ISRF. The content of the information does not necessarily reflect the position or the policy of the United States Government, and no official endorsement should be inferred.

Attached Files

Published - BIP-108-na.pdf

Supplemental Material - bip22934-sup-0001-SuppInfo.docx


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