Implications for collagen I chain registry from the structure of the collagen von Willebrand factor A3 domain complex

Abstract

Fibrillar collagens, the most abundant proteins in the vertebrate body, are involved in a plethora of biological interactions. Plasma protein von Willebrand factor (VWF) mediates adhesion of blood platelets to fibrillar collagen types I, II, and III, which is essential for normal haemostasis. High affinity VWF-binding sequences have been identified in the homotrimeric collagen types II and III, however, it is unclear how VWF recognizes the heterotrimeric collagen type I, the superstructure of which is unknown. Here we present the crystal structure of VWF domain A3 bound to a collagen type III-derived homotrimeric peptide. Our structure reveals that VWF-A3 interacts with all three collagen chains and binds through conformational selection to a sequence that is one triplet longer than was previously appreciated from platelet and VWF binding studies. The VWF-binding site overlaps those of SPARC (also known as osteonectin) and discodin domain receptor 2, but is more extended and shifted toward the collagen amino terminus. The observed collagen-binding mode of VWF-A3 provides direct structural constraints on collagen I chain registry. A VWF-binding site can be generated from the sequences RGQAGVMF, present in the two α1 (I) chains, and RGEOGNIGF, in the unique α2(I) chain, provided that α2(I) is in the middle or trailing position. Combining these data with previous structural data on integrin binding to collagen yields strong support for the trailing position of the α2(I) chain, shedding light on the fundamental and long-standing question of the collagen I chain registry.X-ray crystallography | extracellular matrix V on Willebrand factor (VWF) mediates blood platelet adhesion to sites of vascular damage and is essential for platelet adhesion under conditions of high shear stress. Defective processing and/or mutations in VWF are associated with various haemostatic disorders such as haemolytic uremic syndrome, thrombotic thrombocytopenic purpura, and von Willebrand disease, which is the most common genetic bleeding disorder in humans (1). The mature VWF protein consists of 2,050 amino acid monomers that are disulfide-linked into multimers ranging from 0.5 to 10 MDa in size with the larger multimers being more active in hemostasis. VWF multimer size is regulated by ADAMTS13 through proteolytic cleavage within the VWF A2 domain. Upon vascular damage, the VWF A3 domain interacts with exposed collagens I and III. Subsequent transient interactions between the VWF A1 domain and Glycoprotein Ibα (GPIbα) on the surface of blood platelets reduces platelet velocity to allow subsequent stable platelet adhesion and activation, which ultimately results in thrombus deposition.The crystal structure of the collagen-binding VWF A3 domain has been solved (2-4) and the collagen-binding site within the A3 domain has been mapped in extensive site-directed mutagenesis studies and by NMR (5-7). However, detailed structural information on the VWF-collagen interaction has thus far been lacking.Collagens, the most abundant proteins in mammalian...

The NC2 Domain of Type IX Collagen Determines the Chain Register of the Triple Helix

“…None of the hetero-trimeric combinations of type I collagen was able to approach the efficiency observed with the type III sequence. This is somewhat unexpected from recent speculations based on the crystal structure of the complex between type III collagen peptide and the vWFA3 domain (2), where the authors anticipated an identical interface for a specific type I collagen stagger. On the other hand this is in agreement with the previous observation of much lower affinity of type I collagen to vWFA3 compared with type III (35).…”

Structural and functional features of a collagen-binding matrix protein from the mussel byssus

“…In addition, the binding differs to that of von Willebrand factor since PTMP1 lacks nearly all of the critical interacting residues of the vWFA3 domain 12 . In the von Willebrand factor and other VWA domain proteins, C-terminal helix and linker act as a switch region between an open and a closed state with low and high affinity for metal and ligand 33 .…”

“…It revealed two sequence stretches with homology to the group of von Willebrand factor type A (VWA) domains (Pfam PF00092) with B25% sequence identity andB50% homology to other members of this group, including the von Willebrand factor A3 domain or the I-domains of integrins. VWA domain containing proteins of the blood plasma or the extracellular matrix are often involved in protein-protein interactions including binding of collagen [12][13][14][15] . In case of the von Willebrand factor, binding to partner proteins like glycoprotein Ib or collagen is dependent on conformational changes upon shear forces 16,17 .…”

von Willebrand factor, Jedi knight of the bloodstream

“…74,75 (B) A3 with collagen bound (silver) shown in identical orientation as A1 in (A) and with collagen-contacting residues shown in stick. 77 A nuclear magnetic resonance structure of A3 bound to fibrillar collagen 76 shows an identical binding site (collagen-perturbed residues shown with Ca atom spheres). (C) Detail of 2 superimposed A2 structures, 1 of which shows a 2Å outward movement of the C-terminal a6-helix that may mimic an early step in elongational force-induced A2 unfolding.…”