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 colt and characterized. Soluble proteins capable of succcssful 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 it heterologous N-terminal or C-terminal noncollagenous 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 it resource for the development of biomaterials with new properties