VWC repeats. (A-B) VWC sequence and structure. VWC sequences in VWF are aligned with one another and with structurally characterized VWC domains (A) and shown schematically in relation to structure (B). Conserved cysteines (numbered) and extra cysteines (lettered) are located in both panels A and B. N- and O-linked glycosylation sites are in red (A) and shown as closed and open lollipops, respectively (B). (C) Segment between VWC2 and VWC3 containing 2 local disulfide bonds.¹³  (D) Representative class averages of the A3-CK dimeric bouquet, aligned centering on the fourth globule in the stem region, with a radius of 20 nm. Scale bar represents 10 nm.