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bioRxiv · 10.1101/2025.07.28.667101

Triple-helical ligands selectively targeting the closed αI domain of integrin α2β1

Shibata, S. S.·Oki, H.·Kawahara, K.·Masuda, R.·Fujii, K. K.·Koide, T.
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Abstract

Integrins 1{beta}1, 2{beta}1, 10{beta}1, and 11{beta}1 are known to recognize the GxxGEx motif of the collagen triple helix through their I domains, with the Glu residue engaging the domain via a divalent metal cation. The binding amino acid sequences containing these motifs, identified from native collagen, exhibit low subtype selectivity. Here we identify novel triple-helical peptides that selectively bind the 2I domain independently of Glu and metal ions. Yeast two-hybrid screening of randomized triple-helical peptide libraries yielded non-natural sequences in which the canonical Glu was replaced by aliphatic residues such as Met. X-ray crystal structural analysis of the representative variant GFOGMR in complex with the 2I domain revealed a new binding mode. In this mode, peptides are recognized by the closed, inactive conformation of the 2I domain without metal coordination. This cryptic interaction, likely unused by native ligands, provides a new basis for the design of subtype-specific ligands targeting collagen-binding integrins.

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Shibata, S. S., Oki, H., Kawahara, K., Masuda, R., Fujii, K. K., Koide, T.. 2025-07-29. Triple-helical ligands selectively targeting the closed αI domain of integrin α2β1. https://doi.org/10.1101/2025.07.28.667101

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