Antiparallel Association Research Articles

An Analysis of Fibrous Long Spacing Forms of Collagen

An electron microscopic analysis has been made of the various polymorphic forms of fibrous long spacing (FLS) calf-skin collagen, obtained by precipitation in the presence of chondroitin sulphate.Anti-parallel packing of tropocollagen macroniolecules with opposing ends in register is a feature common to all the FLS polymorphic forms. The glycosaminoglycans-mediated intermolecular contacts which lead to this anti-parallel association can also give rise to non-fibrous symmetrical segments. To account for the observed fibrous structures it is sufficient to suppose that two additional glycosaminoglycans-mediated inrermolecular contacts may occur. One of these causes adjoining tropocollagen units to be mutually overlapped by 0.154 L and the other by 0.425 L (L is the length of a tropocollagen macromolecule). These additional contacts may occur separately, giving FLS I and FLS IV respectively, or they may occur together, given FLS II and 111 and more complex structures.In FLS formation, the usual native-type co...