02103nas a2200241   4500008004100000245010100041210006900142260001400211300001400225490000800239520135400247100002601601700002101627700002101648700002001669700001501689700002101704700001901725700002601744700002401770700001801794856004901812       2011                        eng d00aStructural determinants of vascular endothelial growth factor-D receptor binding and specificity0 aStructural determinants of vascular endothelial growth factorD r  c2011/Feb/  a1507 - 150 v1173 aVascular endothelial growth factors (VEGFs) and their tyrosine kinase receptors (VEGFR-1-3) are central mediators of angiogenesis and lymphangiogenesis. VEGFR-3 ligands VEGF-C and VEGF-D are produced as precursor proteins with long N- and C-terminal propeptides and show enhanced VEGFR-2 and VEGFR-3 binding on proteolytic removal of the propeptides. Two different proteolytic cleavage sites have been reported in the VEGF-D N-terminus. We report here the crystal structure of the human VEGF-D Cys117Ala mutant at 2.9 Å resolution. Comparison of the VEGF-D and VEGF-C structures shows similar extended N-terminal helices, conserved overall folds, and VEGFR-2 interacting residues. Consistent with this, the affinity and the thermodynamic parameters for VEGFR-2 binding are very similar. In comparison with VEGF-C structures, however, the VEGF-D N-terminal helix was extended by 2 more turns because of a better resolution. Both receptor binding and functional assays of N-terminally truncated VEGF-D polypeptides indicated that the residues between the reported proteolytic cleavage sites are important for VEGF-D binding and activation of VEGFR-3, but not of VEGFR-2. Thus, we define here a VEGFR-2-specific form of VEGF-D that is angiogenic but not lymphangiogenic. These results provide important new insights into VEGF-D structure and function.1 aLeppänen, Veli-Matti1 aJeltsch, Michael1 aAnisimov, Andrey1 aTvorogov, Denis1 aAho, Kukka1 aKalkkinen, Nisse1 aToivanen, Pyry1 aYlä-Herttuala, Seppo1 aBallmer-Hofer, Kurt1 aAlitalo, Kari  uhttp://view.ncbi.nlm.nih.gov/pubmed/21148085