Glycosaminoglycan-binding properties and secondary structure of the C-terminus of netrin-1.
Netrins are soluble neurite-outgrowth-promoting proteins related to the laminin B2 chain. Since these proteins and their receptor DCC (the "deleted in colorectal carcinoma" gene product) bind heparin, glycosaminoglycans may modulate their biological actions in a similar fashion as described for several other ligand-receptor systems. Here we show that a polypeptide encompassing the C-terminal cluster of basic amino acids of netrin-1 (i) adopts an alpha-helical conformation in water-trifluoroethanol mixtures according to circular dichroism experiments and (ii) binds electrostatically to heparin with high affinity under physiological ionic conditions (K(D) = 15 nM for the binding to immobilized heparin according to surface plasmon resonance, K(D) = 50 nM in solution as determined with isothermal titration calorimetry). These data indicate that the cluster of basic amino acids at the C-terminus of netrin-1 forms an alpha-helical structural element which can contribute to the glycosaminoglycan-binding activity of this neurotrophic guidance molecule.
Kappler
J
J
Institut für Physiologische Chemie, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 11, Bonn, D-53115, Germany.
Franken
S
S
Junghans
U
U
Hoffmann
R
R
Linke
T
T
Müller
H W
HW
Koch
K W
KW
D000595:Amino Acid Sequence; D000818:Animals; D019921:Biotinylation; D002151:Calorimetry; D002942:Circular Dichroism; D006025:Glycosaminoglycans / Q000378:metabolism*; D006493:Heparin / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D009414:Nerve Growth Factors / Q000737:chemistry* / Q000378:metabolism; D000075388:Netrin-1; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D017433:Protein Structure, Secondary; D020349:Surface Plasmon Resonance; D013696:Temperature; D013997:Time Factors; D025521:Tumor Suppressor Proteins
D006025:Glycosaminoglycans; D009414:Nerve Growth Factors; D010455:Peptides; D025521:Tumor Suppressor Proteins; D000075388:Netrin-1; D006493:Heparin