Amyloidogenic Peptide Fragments Designed From Bacterial Collagen-like Proteins Form Hydrogel

Bacterial collagen-like proteins (CLPs) are composed of tandem Gly-X-Y sequence repeats, but, unlike metazoan collagens, their X- and Y-positions are enriched in hydrophobic and polar residues rather than proline. This distinctive sequence bias suggests that CLPs may harbor sequence features that could promote amyloid-like assembly. Using bioinformatic screening of CLPs, we identified amyloidogenic motifs enriched in alanine, isoleucine, leucine, or valine at the X-position and threonine at the Y-position. Guided by these findings, we designed a focused library of peptides incorporating Gly-X-Thr triplet and the highly abundant GATGVT sextet repeats. Peptides containing Gly-X-Thr produced insoluble fibers, restricting exploration of material properties. In contrast, peptides containing GATGVT repeats formed micrometer-long fibers that physically crosslinked into a robust hydrogel upon centrifugation. Circular dichroism (CD) and Fourier Transform Infrared Spectroscopy (FTIR) revealed length-dependent variations in secondary structure. Imaging of the higher-order structures confirmed densely packed fiber networks while rheological measurements indicated sequence-length-dependent viscoelastic behavior. Notably, a 30 residue GATGVT peptide hydrogel supported high in vitro cell viability of fibroblasts. Overall, these findings suggest that CLPs are an underexplored reservoir of sequence motifs with promising biomaterial potential.