Crystal Structure at 1.7 Å Resolution of VEGF in Complex with Domain 2 of the Flt-1 Receptor

Abstract

Vascular endothelial growth factor (VEGF) is a homodimeric hormone that induces proliferation of endothelial cells through binding to the kinase domain receptor and the Fms-like tyrosine kinase receptor (Flt-1), the extracellular portions of which consist of seven immunoglobulin domains. We show that the second and third domains of Flt-1 are necessary and sufficient for binding VEGF with near-native affinity, and that domain 2 alone binds only 60-fold less tightly than wild-type. The crystal structure of the complex between VEGF and the second domain of Flt-1 shows domain 2 in a predominantly hydrophobic interaction with the "poles" of the VEGF dimer. Based on this structure and on mutational data, we present a model of VEGF bound to the first four domains of Flt-1.

Viral Vascular Endothelial Growth Factors Vary Extensively in Amino Acid Sequence, Receptor-binding Specificities, and the Ability to Induce Vascular Permeability yet Are Uniformly Active Mitogens

“…4B) but was no more potent than the other VEGFs when assayed for binding to a preformed dimer of the same receptor (Fig. 4A) 32 , are clustered on the membrane-facing side of the dimer where they are likely to be able to interact with domain 3 of VEGFR-2 (52,53). This is consistent with a model in which interaction between VEGF and domain 3 of the receptor promotes receptor dimerization by bringing the fourth domains of two monomers into close proximity.…”

“…5). Structural determinations have revealed a groove at each end of the VEGF-A dimer and it has been postulated that these are involved in the recognition of VEGFR-1 (52,53). Residues forming this groove in VEGF-A are indicated in Fig.…”

VEGF Receptor Signaling and Endothelial Function

“…The receptor-binding portion of the VEGF molecules is formed by a homodimer covalently linked by two disul de bridges. VEGF predominantly utilizes hydrohobi c interactions for binding to its receptors (13,14).…”

Novel anti-VEGF chimeric molecules delivered by AAV vectors for inhibition of retinal neovascularization

“…11,12 The VEGF-binding function of Flt-1 has been mapped to the second domain. [13][14][15][16] There have been previous studies with two truncated soluble receptor hybrids, Flt(1-3)-IgG and Flt(1-7)-IgG, consisting of either the first three domains or all seven domains fused to human IgG1-Fc region. 13 The molecule Flt(1-3)-IgG was reported to have the same VEGF-binding affinity as Flt(1-7)-IgG, however Flt(2)-IgG that contains only second domain was not capable of inhibiting VEGF.…”