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Single-chain Vascular Endothelial Growth Factor Variant with Antagonist Activity
Ist Teil von
The Journal of biological chemistry, 2002-10, Vol.277 (43), p.40335-40341
Ort / Verlag
United States: American Society for Biochemistry and Molecular Biology
Erscheinungsjahr
2002
Link zum Volltext
Quelle
MEDLINE
Beschreibungen/Notizen
Vascular endothelial growth factor is a specific endothelial cell mitogen that is essential for the formation of the vascular
system but in the adult individual is involved in several pathological conditions, including cancer. It is a homodimeric protein
that activates its receptor by binding two receptor molecules and inducing dimerization. By mixing two vascular endothelial
growth factor monomers, each with different substitutions, heterodimers with only one active receptor binding site have previously
been prepared. These heterodimers bind the receptor molecule but are unable to induce dimerization and activation. However,
preparation of heterodimers is cumbersome, involving separate expression of different monomers, refolding the mixture, and
separating heterodimers from homodimers. Here we show that a fully functional ligand can efficiently be expressed as a single
protein chain containing two monomers. Single-chain vascular endothelial growth factor is functionally equivalent to the wild-type
protein. By monomer-specific mutagenesis, one receptor binding site was altered. This variant competitively and specifically
antagonizes the mitogenic effect of the wild-type protein on endothelial cells. The results obtained with the single-chain
antagonist show the feasibility of the single-chain approach in directing alterations to single specific regions in natural
homodimeric proteins that would be impossible to target in other ways.