Improved efficacy of soluble human receptor activator of nuclear factor kappa B (RANK) fusion protein by site-directed mutagenesis

Young Jun Son, Jihye Han, Jae Yeon Lee, HaHyung Kim, Taehoon Chun

Research output: Contribution to journalArticle


Soluble human receptor activator of nuclear factor kappa B fusion immunoglobulin (hRANK-Ig) has been considered as one of the therapeutic agents to treat osteoporosis or diseases associated with bone destruction by blocking the interaction between RANK and the receptor activator of nuclear factor kappa B ligand (RANKL). However, no scientific record showing critical amino acid residues within the structural interface between the human RANKL and RANK complex is yet available. In this study, we produced several mutants of hRANK-Ig by replacement of amino acid residue(s) and tested whether the mutants had increased binding affinity to human RANKL. Based on the results from flow cytometry and surface plasmon resonance analyses, the replacement of E<sup>125</sup> with D<sup>125</sup>, or E<sup>125</sup> and C<sup>127</sup> with D<sup>125</sup> and F<sup>127</sup> within loop 3 of cysteine-rich domain 3 of hRANK-Ig increases binding affinity to human RANKL over the wild-type hRANK-Ig. This result may provide the first example of improvement in the efficacy of hRANK-Ig by protein engineering and may give additional information to understand a more defined structural interface between hRANK and RANKL.

Original languageEnglish
Pages (from-to)221-227
Number of pages7
JournalImmunopharmacology and Immunotoxicology
Issue number3
Publication statusPublished - 2015 Jun 1



  • Immunoglobulin fusion protein
  • Mutagenesis
  • Osteoclast
  • Osteoporosis
  • Receptor activator of nuclear factor kappa B

ASJC Scopus subject areas

  • Immunology
  • Immunology and Allergy
  • Pharmacology
  • Toxicology

Cite this