Collagen disulphide bridges

Scott PG, Winterbottom N, Dodd CM, Edwards E, Pearson CH. A role for disulphide bridges in the protein core in the interaction of proteodermatan sulphate and collagen. Biochem Biophys Res Commun 1986 138 1348-1354. 

Fibronectin 550 kDa homodimer (2 x 275 kDa) linked by two disulphide bridges Extracellular matrix Binds collagen, heparin and integrin ... 

The triple helix formation in type III collagen and type III pN-collagen starts exclusively at the set of three disulphide bridges that link the three chains at the C-terminal end. The growth of the helix proceeds from this single nucleus at a rather uniform rate in a zipper-like fashion. 

The nature of the stable cross-linkages in collagen has proved difficult to study because they are so few in number and are of an unusual type. Unlike the keratins, most mature collagens contain no cysteine so that disulphide bridges cannot be formed. Various possibilities have been suggested, but present opinion favours cross-linkages involving lysine and hydroxy lysine. 

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