ABSTRACT 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.
Sagar et al. (Tue,) studied this question.