title: Implications for collagen binding from the crystallographic structure of fibronectin 6FnI1-2FnII7FnI.
abstract: Collagen and fibronectin (FN) are two abundant and essential components of the vertebrate extracellular matrix; they interact directly with cellular receptors and affect cell adhesion and migration. Past studies identified a FN fragment comprising six modules, (6)FnI(1-2)FnII(7-9)FnI, and termed the gelatin binding domain (GBD) as responsible for collagen interaction. Recently, we showed that the GBD binds tightly to a specific site within type I collagen and determined the structure of domains (8-9)FnI in complex with a peptide from that site. Here, we present the crystallographic structure of domains (6)FnI(1-2)FnII(7)FnI, which form a compact, globular unit through interdomain interactions. Analysis of NMR titrations with single-stranded collagen peptides reveals a dominant collagen interaction surface on domains (2)FnII and (7)FnI; a similar surface appears involved in interactions with triple-helical peptides. Models of the complete GBD, based on the new structure and the (8-9)FnI·collagen complex show a continuous putative collagen binding surface. We explore the implications of this model using long collagen peptides and discuss our findings in the context of FN interactions with collagen fibrils.
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
authors.forename: Michèle C
authors.initials: MC
authors.lastname: Erat
authors.forename: Ulrich
authors.initials: U
authors.lastname: Schwarz-Linek
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Pickford
authors.forename: Richard W
authors.initials: RW
authors.lastname: Farndale
authors.forename: Iain D
authors.initials: ID
authors.lastname: Campbell
authors.forename: Ioannis
authors.initials: I
authors.lastname: Vakonakis
mesh_terms: D000818:Animals; D001665:Binding Sites; D002465:Cell Movement; D002942:Circular Dichroism / Q000379:methods; D003094:Collagen / Q000737:chemistry*; D018360:Crystallography, X-Ray / Q000379:methods*; D005353:Fibronectins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D010455:Peptides / Q000737:chemistry; D010843:Pichia / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D005353:Fibronectins; D010455:Peptides; D011994:Recombinant Proteins; D012997:Solvents; D003094:Collagen