Collagen fibrils of sea cucumber (Apostichopus japonicus) are heterotypic.

Sea cucumbers attracted increasing interest due to its nutritional functions. Collagen is the most important structural biomacromolecule in sea cucumber body wall, and is highly related to the textual properties and food quality of sea cucumber. In this study, the type of constituent collagens of sea cucumber collagen fibrils was investigated, employing a commercially important species Apostichopus japonicus as the material. Proteomics and bioinformatics analysis revealed that collagen fibrils of A. japonicas are heterotypic. Two clade A and one clade B fibrillar collagens and two FACIT collagens were identified from the fibrils. Besides, the heterogeneity was also revealed in the pepsin-solubilized collagen (PSC) of A. japonicus by using the proteomics strategy. It implied that the previous conclusions on the type of sea cucumber collagen deduced from SDS-PAGE analysis should be rechecked. The results provided novel insight into the composition of sea cucumber collagen fibrils.