Expanding the Family of Collagen Proteins: Recombinant Bacterial Collagens of Varying Composition Form Triple-Helices of Similar Stability

摘要

The presence of the (Gly-Xaa-Yaa)_n open reading frames in different bacteria predicts the existence of an expanded family of collagen-like proteins, To further explore the triple-helix motif and stabilization mechanisms in the absence of hydroxyproline (Hyp), predicted novel collagen-like proteins from Gram-positive and -negative bacteria were expressed in Escherichia coli and characterized. Soluble proteins capable of successful folding and in vitro refolding were observed for collagen proteins from Methylobacterium sp 4—46, Rhodopseudomonas palustris and Solibacter usitatus. In contrast, all protein constructs from Clostridium perfringens were found predominantly in inclusion bodies. However, attachment of a heterologous N-terminal or C-terminal noneollagenous folding domain induced the Clostridium perfringens collagen domain to fold and become soluble. The soluble constructs from different bacteria had typical collagen triple-helical features and showed surprisingly similar thermal stabilities despite diverse amino acid compositions. These collagen-like proteins provide a resource for the development of biomaterials with new properties.