Collagen VII triple-helices form an anti-parallel dimer, associating through disulfide bonds formed in a 60-nm overlap (NC2 domain) of the amino terminal triple helical ends. A portion of this region is proteolytically removed (Morris et al. 1986, Chen et al. 2001) prior to aggregation of dimers into anchoring fibrils (Lundstrum et al. 1986).