Description: Binds tightly to hydroxyapatite. Appears to form an integral part of the mineralized matrix. Probably important to cell-matrix interaction. (www.uniprot.org) Produced in E.coli as a single, non-glycosylated, polypeptide chain containing 321 amino acids (fragment 17-314). The SPP1 protein is fused to 20 amino acid His Tag at N-terminus.