Phage-Display-Derived Peptide Specific to Carbamylated Protein

Yuhao Ma; Meng Wu; Shuhui Li; Marcello Tonelli; Larry D Unsworth

doi:10.1021/acsomega.0c05481

Phage-Display-Derived Peptide Specific to Carbamylated Protein

ACS Omega. 2021 Jan 25;6(4):3079-3089. doi: 10.1021/acsomega.0c05481. eCollection 2021 Feb 2.

Authors

Yuhao Ma¹, Meng Wu², Shuhui Li², Marcello Tonelli³, Larry D Unsworth^{1

2}

Affiliations

¹ Department of Biomedical Engineering, University of Alberta, Edmonton, Alberta T6G 2V2, Canada.
² Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada.
³ Department of Medicine, University of Calgary, Calgary, Alberta T2N 1N4, Canada.

Abstract

Protein carbamylation has been linked with diseases commonly associated with patients with reduced kidney function. Carbamylated human serum albumin (cHSA), which has been proven to be nephrotoxic and associated with heart failure for chronic kidney disease (CKD) patients, was chosen for our study. Through phage display against cHSA, one specific peptide sequence (cH2-p1) was identified with higher selectivity toward cHSA over native HSA. The cH2-p1 peptide was synthesized, and its target binding was analyzed through isothermal titration calorimetry (ITC). The result showed that cH2-p1 was able to bind cHSA of different levels of carbamylation with a similar dissociation constant of ∼1.0 × 10^-4 M. This peptide also showed a binding specificity to carbamylated fibrinogen (cFgn), while not binding to native Fgn at all. For better understanding of the binding mechanism of cH2-p1, competitive binding of cH2-p1 and anti-homocitrulline to cHSA was performed, and the result revealed that cH2-p1 may bind to homocitrulline residues in a similar manner to the antibody. A molecular docking study was further performed to investigate the favored binding conformation of homocitrulline residue to cH2-p1. This work demonstrates the potential of peptides as a specific binding element to carbamylated proteins.