Expression and characterization of a human BMP-7 variant with improved biochemical properties

Protein Expr Purif. 2008 Feb;57(2):312-9. doi: 10.1016/j.pep.2007.09.016. Epub 2007 Oct 1.

Abstract

Bone morphogenetic protein-7 (BMP-7, OP-1) is a secreted growth factor that is predominantly known for its osteoinductive properties, though it has also been implicated as having a role in mammalian kidney development. Clinical efficacy of recombinant BMP-7 has been demonstrated in the treatment of orthopedic injuries through topical application. However, the pharmaceutical development of recombinant BMP-7 for systemic delivery has presented many challenges. Specifically, the expression level of recombinant mature BMP-7 protein in mammalian cells is very low, the molecule has poor solubility at neutral pH, and intracellular proteolytic processing events result in a secreted BMP-7 having multiple amino-termini, creating a heterogeneous mixture of proteins. Utilizing structural information, we have designed and generated a number of rational BMP-7 mutations that improved both expression levels in mammalian cells and solubility at neutral pH, while limiting the amino-terminal heterogeneity of the mature protein. Introduction of these mutations did not compromise BMP-7 in vitro bioactivity. This improved BMP-7 molecule is better suited for pharmaceutical development and clinical advancement for indications where systemic delivery may be required.

MeSH terms

  • Alkaline Phosphatase / metabolism
  • Amino Acid Motifs
  • Amino Acid Sequence
  • Animals
  • Bone Morphogenetic Protein 7
  • Bone Morphogenetic Proteins / chemistry
  • Bone Morphogenetic Proteins / genetics
  • Bone Morphogenetic Proteins / metabolism*
  • CHO Cells
  • Cell Line
  • Cricetinae
  • Cricetulus
  • Dimerization
  • Humans
  • Models, Molecular
  • Molecular Sequence Data
  • Mutant Proteins / biosynthesis
  • Mutant Proteins / genetics
  • Mutant Proteins / metabolism*
  • Mutation / genetics
  • Protein Precursors / chemistry
  • Protein Precursors / metabolism
  • Protein Processing, Post-Translational
  • Rats
  • Transforming Growth Factor beta / chemistry
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*

Substances

  • BMP7 protein, human
  • Bmp7 protein, rat
  • Bone Morphogenetic Protein 7
  • Bone Morphogenetic Proteins
  • Mutant Proteins
  • Protein Precursors
  • Transforming Growth Factor beta
  • Alkaline Phosphatase