Composition‐dependent multivalency of peptide–peptide interactions revealed by tryptophan‐scanning mutagenesis

• Published in: Journal of peptide science 2021-06, Vol.27 (6), p.e3310-n/a
• Main Authors: Yu, Lanlan, Zheng, Yongfang, Fang, Xiaocui, Zou, Yimin, Wang, Chenxuan, Yang, Yanlian, Wang, Chen
• Format: Article
• Language: English
• Subjects: Binding energy; Combinatorial analysis; Composition; Energy; flow cytometry; Glycine; Hydrogen bonding; Hydrogen bonds; Indoles; Nonlinear systems; Octapeptides; Peptides; peptide–peptide interaction; Scanning mutagenesis; Thermodynamics; Tryptophan; tryptophan mutation
• ISSN: 1075-2617; 1099-1387
• DOI: 10.1002/psc.3310

We have examined in this contribution the composition dependence of binding characteristics in peptide–peptide interactions between an oligopeptide octa‐glycine and a series of tryptophan‐containing octapeptides. The binding energy associated with tryptophan–glycine interactions manifests pronounced stepwise binding characteristics as the number of tryptophan increases from 0 to 8 in the octapeptides consisting only of glycine and can be attributed to mono‐, di‐, and tri‐valent peptide–peptide interactions. At the same time, only weak fluctuations in binding energy were observed as the number of tryptophan increases from 2 to 7. Such distinctive nonlinearity of composition‐dependent tryptophan–glycine binding energy characteristics due to continuously varying tryptophan compositions in the octapeptides could be considered as a reflection of combinatorial contributions due to the hydrogen bonds originated from the indole moieties of tryptophan with the main chains of octapeptide of glycine containing N–H and C=O moieties and the van der Waals interactions (including π–π and π–CH interactions) between peptides. The cooperative binding characteristics of interpeptide interactions between an oligopeptide octa‐glycine and a series of tryptophan‐containing octapeptides have been revealed by a flow cytometry‐based assay for quantification of affinity. The binding energy associated with tryptophan‐glycine interactions manifests non‐linear stepwise binding characteristics as the increased number of tryptophan. The nonlinearity of composition‐dependent tryptophan‐glycine binding energy characteristics reflects combinatorial contributions of different types of intermolecular interactions.