Structural Implications of Banding in Unstained Collagen

摘要: THE three currently accepted dimensional models for the structure of collagen fibril predict alternating regions high and low density along length fibril, with a repeat (D) about 650 A (Fig. 1a)1–3. As in previous two “modified quarterstagger” model4,5, denser (A bands) are 0.4 D length, less dense or “hole” (B 0.6 D, tropocollagen molecular is 4.4 D. The electron micrographs negatively stained native reconstituted collagen, on which largely based, vividly display large banded features have been interpreted as due to higher permeability B bands metal stain6,7. Although unstained fibrils could be expected reflect intrinsic longitudinal distribution, very few studies included such micrographs, these were not detailed8,9. Consequently, we re-examined by simple technique. observed patterns seem conflict above prevailing interpretation negative staining collagen.