(516av) Biosynthesis Of Collagen-Like Protein Polymers

Collagen is the most abundant human protein and has been widely used for tissue engineering applications due to its natural function in the extra cellular matrix. Natural collagen self assembles into a triple helix to form long fibers. One of the key aspects of its stability is the posttranslational modification of a large percentage of the prolines into 4-hydroxyproline. Here we have created a recombinant construct based on the repeating unit of the collagen consensus sequence (PPG) that can self assemble into a stable triple helix. Since the posttranslational modifications are not available in prokaryotic synthesis, we have stabilized the collagenous region by fusing it to a very stable trimer-forming leucine zipper domain. This has allowed us to express in the soluble fraction a synthetic protein polymer containing 42 PPG repeats fused to the stabilizing domain. In addition, to facilitate cell binding to the protein polymer, we have created and expressed a construct containing repeats of the cell-binding domain RGD integrated into the collagen domain. Then, the structural, mechanical and cell binding properties of these polymers were studied. Recombinant methods will allow us to further tailor the construct for various tissue-engineering applications and also test the limits of the stabilizing domain by increasing the length of the collagen-like region.