Refolding of Collagen IV and Other Collagens as Monitored by Electron Microscopy
In vivo, the formation of the triple helical structure is one of the important post translational events leading to the collagen precursor molecule. A prerequisite for the correct folding to an intact triple helix is a correct alignment and association of three polypeptide chains. As demonstrated for collagen I and III (Bächinger et al., Eur. J. Biochem. (1980) 106, 619; Bruckner et al., Eur. J. Biochem. (1978) 90, 595) this is facilitated by carboxyterminal crosslinks or peptides. The mechanism of collagen folding was described by a zipper model which proceeds from the C- to the N- terminus in a rather uniform rate being determined by the cis/trans isomerisation of proline peptide bonds.