Comparative structural studies of reconstituted and native type I and type II collagen fibrils by low-angle X-ray diffraction.

Acid-soluble and pepsin-soluble type I collagen from calf skin and pepsin-soluble type II collagen from bovine articular cartilage were precipitated in fibrillar form by various methods. Reconstituted native-like fibrils were analysed by low-angle X-ray diffraction, and the patterns were compared with those obtained with native type I (rat tail tendon) and type II fibrils (bovine articular cartilage). For both orientated and disorientated forms of these samples, we measured the ratio of the first/third-order intensities of the meridional diffraction peaks which are associated with the gap-filling. The values obtained with the reconstituted native-like fibrils (types I and II) were double and 20-times the values, respectively, measured for rat tail tendon and bovine articular cartilage. These differences reflect the extent of specific interactions of other components (proteoglycans) at the gap level along the collagen fibrils in the two tissues.