title: Elucidation of the structural features of heparan sulfate important for interaction with the Hep-2 domain of fibronectin.
abstract: The interaction of fibronectin with cell surface heparan sulfate proteoglycans is important biologically in inducing reorganization of the cytoskeleton and the assembly of focal adhesions. The major heparan sulfate-binding site in fibronectin, which is also implicated in these morphological events, is the COOH-terminal Hep-2 domain. We describe the first extensive study of the structural determinants required for the interaction between heparan sulfate/heparin and Hep-2. It is clear that, in heparan sulfate, there is a very prominent role for N-sulfate groups, as opposed to a relatively small apparent contribution from carboxyl groups. Furthermore, a minimal octasaccharide binding sequence appeared to contain at least two 2-O-sulfated iduronate residues, but no 6-O-sulfate groups. However, affinity was enhanced by the presence of 6-O-sulfates, and the interaction with Hep-2 also increased progressively with oligosaccharide size up to a maximum length of a tetradecasaccharide. This overall specificity is compatible with recent information on the structure of Hep-2 (Sharma, A., Askari, J. A., Humphries, M. J., Jones, E. Y., and Stuart, D. I. (1999) EMBO J. 18, 1468-1479) in which two separate, positively charged clusters, involving up to 11 basic amino acid residues (mostly arginines with their preferential ability to co-ordinate sulfate groups), could form a single extended binding site.
authors.affiliation: Cancer Research Campaign Department of Medical Oncology, University of Manchester, Christie Hospital NHS Trust, Manchester M20 4BX, United Kingdom. mlyon@picr.man.ac.uk
authors.forename: M
authors.initials: M
authors.lastname: Lyon
authors.forename: G
authors.initials: G
authors.lastname: Rushton
authors.forename: J A
authors.initials: JA
authors.lastname: Askari
authors.forename: M J
authors.initials: MJ
authors.lastname: Humphries
authors.forename: J T
authors.initials: JT
authors.lastname: Gallagher
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002846:Chromatography, Affinity; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D005353:Fibronectins / Q000737:chemistry / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism; D006497:Heparan Sulfate / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D015394:Molecular Structure
chemical_list: D005353:Fibronectins; D006025:Glycosaminoglycans; D006497:Heparan Sulfate