The invention relates to peptides including DEDE(SSD)nDEG indicated by SEQ NO. 1, RRRDEDE(SSD)nDEG indicated by SEQ NO. 2, RRRGDEDE(SSD)nDEG indicated by SEQ NO. 3, and LKKLKKLDEDE(SSD)nDEG indicated by SEQ NO. 4, wherein n is an integer from 2 to 20. The invention also relates to phosphorylating these peptides at multiple amino acid sites by employing casein kinases. These phosphorylated peptides may be used in various applications such as forming mineralized collagen fibrils and biomimetic composites for use in tissue repair and regeneration.