The complete primary structure of mouse alpha 2(IV) collagen. Alignment with mouse alpha 1(IV) collagen.

We have determined the nucleotide and amino acid sequences of mouse alpha 2(IV) collagen which is 1707 amino acids long. The primary structure includes a putative 28-residue signal peptide and contains three distinct domains: 1) the 7 S domain (residues 29-171), which contains 5 cysteine and 8 lysine residues, is involved in the cross-linking and assembly of four collagen IV molecules; 2) the triple-helical domain (residues 172-1480), which has 24 sequence interruptions in the Gly-X-Y repeat up to 24 residues in length; and 3) the NC1 domain (residues 1481-1707), which is involved in the end-to-end assembly of collagen IV and is the most highly conserved domain of the protein. Alignment of the primary structure of the alpha 2(IV) chain with that of the alpha 1(IV) chain reported in the accompanying paper (Muthukumaran, G., Blumberg, B., and Kurkinen, M. (1989) J. Biol. Chem. 264, 6310-6317) suggests that a heterotrimeric collagen IV molecule contains 26 imperfections in the triple-helical domain. The proposed alignment is consistent with the physical data on the length and flexibility of collagen IV.