Location of N445K,T mutations within the GDF5 dimer.

<p>(A) GDF5 dimer (light, dark grey) linked via a disulfide bridge (PDB: 3EVS). Amino acid residues predicted to form the BMP type I receptor interface are indicated in orange, the BMP type II receptor interface in green, and the NOG interface in magenta. Amino acids that bind to BMPRI and NOG are indicated in violet, amino acids important for BMPRII and NOG binding are indicated in cyan. Amino acid N445 is indicated in yellow. Note, the position N445 is within the receptor interaction site as well as within the NOG interaction site. (B) Venn diagram indicates predicted GDF5 amino acids important for NOG and receptor interaction. (C) The mutated asparagine of the GDF5 N445K,T mutants is located in the region between the third and fourth conserved cysteine of the mature domain of the TGFβ superfamily, also called the “wrist” epitope of the hand-like BMP/GDF monomer. Note that the divergent BMP9, BMP10 pair share a lysine at this position.