Proposed alignment of helical interruptions in the two subunits of the basement membrane (type IV) collagen

We have isolated a cDNA clone for part of the alpha 2 type IV collagen (pCIV-2-176). Deoxynucleotide sequence analysis shows that this clone codes for 439 amino acids from the helical domain adjacent to the C-terminal globular domain of the alpha 2 (IV) chain. By aligning the deduced amino acid sequence of the alpha 2 (IV) chain with the published sequence for the alpha 1 (IV) chain, we find that all interruptions in the alpha 1 (IV) chain coincide with an interruption in the alpha 2 (IV) chain. Additional interruptions in the alpha 2 (IV) chain exist, however, three out of the four analysed only slightly disturb the collagen triple helix.