[Full-length expression optimization and applications of recombinant human type I and type II collagen α1 chains]

To obtain full-length recombinant human type I and type II collagen α1 chains with biological activity, potential cleavage sites and surrounding amino acid sequences that may exist during heterologous expression of native human type I and type II collagen α1 chains in Komagataella phaffii were mutated. Two variants were constructed to enable their intact expression in the Komagataella phaffii. Through purification techniques, complete full-length recombinant human type I and type II collagen α1 chain variants were obtained. Both variants demonstrated excellent stability under high-density fermentation conditions, with expression levels quantified by UV reaching 18.7 g/L (type I) and 17.3 g/L (type II), respectively. High-purity products were obtained after purification. These results provide an important reference for the development of highly stable full-length recombinant collagen α chains. The recombinant collagen hydrogels prepared from the two types of collagen exhibited similar biological functions to those of hydrogels prepared from natural collagen and can be utilized as novel biological materials in the medical device field.