Regulating the bioactivity of non-glycosylated recombinant human bone morphogenetic protein-2 to enhance bone regeneration

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is the predominant growth factor that effectively induces osteogenic differentiation in orthopedic procedures. However, the bioactivity and stability of rhBMP-2 are intrinsically associated with its sequence, structure, and storage conditions. In this study, we successfully determined the amino acid sequence and protein secondary structure model of non-glycosylated rhBMP-2 expressed by an E. coli expression system through X-ray crystal structure analysis. Furthermore, we observed that acidic storage conditions enhanced the proliferative and osteoinductive activity of rhBMP-2. Although the osteogenic activity of non-glycosylated rhBMP-2 is relatively weaker compared to glycosylated rhBMP-2; however, this discrepancy can be mitigated by incorporating exogenous chaperone molecules. Overall, such information is crucial for rationalizing the design of stabilization methods and enhancing the bioactivity of rhBMP-2, which may also be applicable to other growth factors.