Structure
Volume 7, Issue 4, 15 April 1999, Pages 381-390
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Research Article
NMR structure of the human oncofoetal fibronectin ED-B domain, a specific marker for angiogenesis

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Abstract

Background: The process of angiogenesis (i.e. the formation of new bloodvessels from pre-existing ones) is fundamental to physiological processes such as reproduction, development and repair, as well as to pathological conditions such as tumor progression, rheumathoid arthritis and ocular disorders. The oncofoetal ED-B domain, a specific marker of angiogenesis, consists of 91 amino acid residues that are inserted by alternative splicing into the fibronectin (FN) molecule.

Results: The NMR structure of the ED-B domain is reported and reveals important differences from other FN type III domains. A comparison of the ED-B domain with the crystal structure of a four-domain FN fragment shows the novel features of ED-B to be located in loop regions that are buried at interdomain interfaces, and which therefore largely determine the global shape of the FN molecule. The negatively charged amino acids in this highly acidic protein are uniformly distributed over the molecular surface, with the sole exception of a solvent-exposed hydrophobic patch that represents a potential specific recognition site. Epitope mapping with 82 decapeptides that span the ED-B sequence revealed that three ED-B-specific monoclonal antibodies, which selectively target newly forming blood vessels in tumor-bearing mice, bind to adjacent regions on the ED-B surface.

Conclusions: The NMR structure enables the identification of a large surface area of the ED-B domain that appears to be accessible in vivo, opening up new diagnostic and therapeutic opportunities. Furthermore, the mapping of specific monoclonal antibodies to the three-dimensional structure of the ED-B domain, and their use in angiogenesis inhibition experiments, provides a basis for further investigation of the role of the ED-B domain in the formation of new blood vessels.

Keywords

angiogenesis marker
ED-B domain
fibronectin isoform
NMR

Cited by (0)

R Fattorusso, M Pellecchia, F Viti, D Neri and K Wüthrich (corresponding author), Institut für Molekularbiologie und Biophysik, Eidgenössische Technische Hochschule Hönggerberg, CH-8093 Zürich, Switzerland.

Present address for R Fattorusso, Facolta’ di Scienze Ambientali, Seconda Universita’ di Napoli, Via Arena 22, 81100 Caserta, Italy.

Present address for M Pellecchia, Biophysics Research Division, The University of Michigan, 930 North University Avenue, Ann Arbor, MI 48109, USA.

P Neri, Dipartimento di Biologia Molecolare, Sez. Biochimica, Universita’ di Siena, 53100 Siena, Italy.