A proximity-driven and regioselective peptide bicyclization (PReP-Bicyc) approach for phage display libraries
8 affiliations
- 1Texas A&M Drug Discovery Center and Department of Chemistry, College of Arts and Sciences, Texas A&M University, College Station, TX, USA.
- 2Institute of Biosciences and Technology and Department of Translational Medical Sciences, College of Medicine, Texas A&M University, Houston, USA.
- 3Texas A&M Drug Discovery Center and Department of Chemistry, College of Arts and Sciences, Texas A&M University, College Station, TX, USA. [email protected].
- 4Texas A&M Drug Discovery Center and Department of Chemistry, College of Arts and Sciences, Texas A&M University, College Station, TX, USA. [email protected].
- 5Institute of Biosciences and Technology and Department of Translational Medical Sciences, College of Medicine, Texas A&M University, Houston, USA. [email protected].
- 6Department of Biochemistry and Biophysics, College of Agriculture and Life Sciences, Texas A&M University, College Station, TX, USA. [email protected].
- 7Department of Cell Biology and Genetics, College of Medicine, Texas A&M University, College Station, TX, USA. [email protected].
- 8Department of Pharmaceutical Sciences, Lerma Rangel College of Pharmacy, Texas A&M University, College Station, TX, USA. [email protected].
Abstract
Peptide macrocyclization is a powerful strategy to enhance the stability, rigidity, binding affinity, and cellular permeability of therapeutic candidates. Peptide bicycles provide superior conformational constraint but remain difficult to generate in phage-displayed libraries because of limited phage-compatible chemistries. Here, we report Proximity-Driven, Regioselective Peptide Bicyclization (PReP-Bicyc), a general, additive-free, phage-compatible strategy for site-selective bicyclization of peptide libraries. PReP-Bicyc uses a rationally designed linker, 4,6-dichloropyrimidine-2-carbonitrile (4,6-DCCPm), that rapidly reacts with an N-terminal cysteine through nitrile-mediated thiazoline formation, followed by proximity-driven intramolecular thiol arylation of two internal cysteines. The resulting bicycles form efficiently under mild conditions while preserving phage viability. Screening a PReP-Bicyc-modified CX₄CX₄C library against programmed cell death protein 1 (PD-1) identifies sub-micromolar bicyclic ligands (best Kd ≈ 400 nM) that selectively label PD-1-expressing cells and inhibit the PD-1/PD-L1 interaction. PReP-Bicyc provides a robust platform for evolving high-affinity bicyclic ligands and expands the chemical toolkit for macrocyclic therapeutic discovery.
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BibTeX
@article{jin2026proximitydriven,
title = {{A proximity-driven and regioselective peptide bicyclization (PReP-Bicyc) approach for phage display libraries}},
author = {Guoqing Jin and Yifan Shi and Shihui Fan and Lai Hoang Son Le and Wenyue Cao and Thuzar Hla Shwe and Zihan Anna Zhang and Demonta D Coleman and Satyanarayana Nyalata and Joshua Trae Hampton and Wenshe Ray Liu},
journal = {Nature Communications},
year = {2026},
month = oct,
doi = {10.1038/s41467-026-77740-5},
url = {https://www.nature.com/articles/s41467-026-77740-5},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - A proximity-driven and regioselective peptide bicyclization (PReP-Bicyc) approach for phage display libraries
AU - Guoqing Jin
AU - Yifan Shi
AU - Shihui Fan
AU - Lai Hoang Son Le
AU - Wenyue Cao
AU - Thuzar Hla Shwe
AU - Zihan Anna Zhang
AU - Demonta D Coleman
AU - Satyanarayana Nyalata
AU - Joshua Trae Hampton
AU - Wenshe Ray Liu
PY - 2026
DA - 2026/10/03
JO - Nature Communications
DO - 10.1038/s41467-026-77740-5
UR - https://www.nature.com/articles/s41467-026-77740-5
AB - Peptide macrocyclization is a powerful strategy to enhance the stability, rigidity, binding affinity, and cellular permeability of therapeutic candidates. Peptide bicycles provide superior conformational constraint but remain difficult to generate in phage-displayed libraries because of limited phage-compatible chemistries. Here, we report Proximity-Driven, Regioselective Peptide Bicyclization (PReP-Bicyc), a general, additive-free, phage-compatible strategy for site-selective bicyclization of peptide libraries. PReP-Bicyc uses a rationally designed linker, 4,6-dichloropyrimidine-2-carbonitrile (4,6-DCCPm), that rapidly reacts with an N-terminal cysteine through nitrile-mediated thiazoline formation, followed by proximity-driven intramolecular thiol arylation of two internal cysteines. The resulting bicycles form efficiently under mild conditions while preserving phage viability. Screening a PReP-Bicyc-modified CX₄CX₄C library against programmed cell death protein 1 (PD-1) identifies sub-micromolar bicyclic ligands (best Kd ≈ 400 nM) that selectively label PD-1-expressing cells and inhibit the PD-1/PD-L1 interaction. PReP-Bicyc provides a robust platform for evolving high-affinity bicyclic ligands and expands the chemical toolkit for macrocyclic therapeutic discovery.
SN - 2041-1723
ER -